Journal of Botany http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Structure and Stability of Cocoa Flowers and Their Response to Pollination Sun, 02 Mar 2014 10:18:52 +0000 http://www.hindawi.com/journals/jb/2014/513623/ This study investigated the position of staminodes around the style of cocoa flowers and the stability of cocoa flowers relative to pollination and seasonality. Cocoa flowers were categorized into converging, ≤1.20 mm; parallel, 1.21–2.40 mm, and splay ≥2.41 mm, depending on the distance between the staminode and style. Some flowers were hand pollinated while others were not and were excluded from insect visitors. Proportions of flowers of converging (56.0%), parallel (37.5%), and splay (6.5%) remained similar along the vertical plane of cocoa trees. Although pollination rates of flowers with splay staminodes were the lowest, the overall pollination success of cocoa trees was not significantly affected because of the small proportion of splay flowers.The stability of the cocoa flowers depended on both the season and pollination. During the dry season, unpollinated flowers of cocoa trees showed a flower-stability ratio of 72% on the second day, while the flower-stability ratio was 94% in the wet season. Pollinated (senescent) flowers had a stability ratio of 95% after 5 days during the wet season, but all pollinated flowers dropped after 5 days in the dry season, indicating that seasonal factors, such as water stress, can have dramatic effects on cocoa yields. Kofi Frimpong-Anin, Michael K. Adjaloo, Peter K. Kwapong, and William Oduro Copyright © 2014 Kofi Frimpong-Anin et al. All rights reserved. Fruit Morphology as Taxonomic Features in Five Varieties of Capsicum annuum L. Solanaceae Mon, 17 Feb 2014 11:33:52 +0000 http://www.hindawi.com/journals/jb/2014/540868/ Variations in the fruit morphological features of Capsicum annuum varieties were studied. Varieties studied include var. abbreviatum, var. annuum, var. accuminatum, var. grossum, and var. glabriusculum. The fruit morphology revealed attenuated fruit shape with rounded surfaces in var. glabriusculum, and cordate fruit shape with flexuous surface in var. annuum, abbreviatum and accuminatum. The fruit is a berry and may be green, yellow, or red when ripe. The fruit epidermal cell-wall patterns are polygonal in shape with straight and curved anticlinal walls in all the five varieties. The fruit of var. abbreviatum and var. grossum is trilocular, while that of var. accuminatum and annuum is bilocular, and that of var. glabriusculum is tetralocular. Capsicum annuum var. glabriusculum had the highest mean number of seeds (108.4) and var. annuum had the lowest number of seeds (41.3) per fruit. The fruit is conspicuously hollowed in var. glabriusculum, accuminatum, and annuum but inconspicuously hollowed in var. abbreviatum and var. grossum. These features are shown to be good taxonomic characters for delimiting the five varieties of Capsicum annuum. Daniel Andrawus Zhigila, Abdullahi Alanamu AbdulRahaman, Opeyemi Saheed Kolawole, and Felix A. Oladele Copyright © 2014 Daniel Andrawus Zhigila et al. All rights reserved. Anatomy and Histochemistry of Roots and Shoots in Wild Rice (Zizania latifolia Griseb.) Thu, 06 Feb 2014 12:28:14 +0000 http://www.hindawi.com/journals/jb/2014/181727/ Wild rice (Zizania latifolia Griseb.) is a famous, perennial, emergent vegetable in China. The current work explores the anatomy and histochemistry of roots, stems, and leaves and the permeability of apoplastic barriers of wild rice. The adventitious roots in wild rice have suberized and lignified endodermis and adjacent, thick-walled cortical layers and suberized and lignified hypodermis, composed of a uniseriate sclerenchyma layer (SC) underlying uniseriate exodermis; they also have lysigenous aerenchyma. Stems have a thickened epidermal cuticle, a narrow peripheral mechanical ring (PMR), an outer ring of vascular bundles, and an inner ring of vascular bundles embedded in a multiseriate sclerenchyma ring (SCR). There is evidence of suberin in stem SCR and PMR sclerenchyma cells. Sheathing leaves are characterized by thick cuticles and fibrous bundle sheath extensions. Air spaces in stems and leaves consist of mostly lysigenous aerenchyma and pith cavities in stems. Apoplastic barriers are found in roots and stems. Chaodong Yang, Xia Zhang, Junkai Li, Manzhu Bao, Dejiang Ni, and James L. Seago Jr. Copyright © 2014 Chaodong Yang et al. All rights reserved. Composted Rice Husk Improves the Growth and Biochemical Parameters of Sunflower Plants Wed, 22 Jan 2014 12:51:51 +0000 http://www.hindawi.com/journals/jb/2014/427648/ The present study investigated the effects of composted rice husk (5 and 26; 10 g/2 kg of soil/pot) on growth and biochemical parameters of sunflower plants at the 30th and 60th day of germination. Result showed significant improvement in growth and biochemical parameters of plants as compared to control plants treated with uncomposted organic fertilizer. However, the effects vary with the microbial treatments involved in the composting of rice husk like composted with T. hamatum (JUF1), bradyrhizobium sp-II (JUR2) alone, and JUF1 in combination with Rhizobium sp-I (JUR1) were found effective in improving the shoot and root lengths, total chlorophyll, carbohydrate, crude protein, and mineral (nitrogen and phosphorus) content of sunflower plants. It indicates that composted rice husk with improved total carbohydrate and protein contents may increase the soil fertility by improving its organic content. Rabia Badar and Shamim A. Qureshi Copyright © 2014 Rabia Badar and Shamim A. Qureshi. All rights reserved. Phenolic Composition and Antioxidant and Antimicrobial Activities of Extracts Obtained from Crataegus azarolus L. var. aronia (Willd.) Batt. Ovaries Calli Mon, 20 Jan 2014 12:43:02 +0000 http://www.hindawi.com/journals/jb/2014/623651/ Objective. Plant cell culture is an innovative technology to produce a variety of substances. Numerous plants synthesize among their secondary metabolites phenolic compounds which possess antioxidant and antimicrobial effects. Hawthorn (Crataegus) is one of these plants which has long been used in folk medicine and is widely utilized in pharmaceutical preparations mainly in neuro- and cardiosedative actions. Methods and Results. The production of polyphenol by fifty-two-week-old Crataegus azarolus var. aronia calli was studied in relation to growth variation and antioxidant and antimicrobial capacity within a subcultured period. The DPPH and ABTS+ assays were used to characterize the antioxidant actions of the callus cultures. Antimicrobial activity was tested by using disc diffusion and dilution assays for the determination of the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values of each active extract. High TEACDPPH, TEACABTS, and antimicrobial activity was observed when maximal growth was reached. An optimum of total phenol, proanthocyanidins, flavonoid, (−)-epicatechin, procyanidin B2, chlorogenic acid, and hyperoside was produced during this period. Conclusion. Antioxidant and antimicrobial activities were strongly correlated with total phenols and total flavonoids. Crataegus azarolus var. aronia cells culture represents an important alternative source of natural antioxidants and antimicrobials. Radhia Bahri-Sahloul, Radhia Ben Fredj, Naima Boughalleb, Jihène Shriaa, Saâd Saguem, Jean-Louis Hilbert, Francis Trotin, Saida Ammar, Sadok Bouzid, and Fethia Harzallah-Skhiri Copyright © 2014 Radhia Bahri-Sahloul et al. All rights reserved. Effect of NPK and Poultry Manure on Growth, Yield, and Proximate Composition of Three Amaranths Sun, 12 Jan 2014 00:00:00 +0000 http://www.hindawi.com/journals/jb/2014/828750/ The study compares the growth, yield, and proximate composition of Amaranthus hybridus, Amaranthus cruentus, and Amaranthus deflexus, grown with poultry manure and NPK in relation to the unfertilized soil of Ilorin, Nigeria. Viable seeds of the Amaranths raised in nursery for two weeks were transplanted (one plant per pot) into unfertilized soil (control) and soils fertilized with either NPK or poultry manure (PM) at 30 Kg ha−1 rate arranged in randomized complete block design with four replicates. Data were collected on plant height, stem girth, number of leaves, leaf area, and number of branches from 1 week after transplanting (1 WAT). Fresh weight, dry weight, and proximate composition were determined at 6 WAT. Except for the length, breadth, and number of leaves, the order of growth parameters and yield in the three Amaranthus species was NPK > PM > control. NPK grown Amaranthus species had the highest protein while PM-grown vegetables had the highest ash content. Crude fibre in A. cruentus grown with PM was significantly higher than NPK and the control. The NPK treatment of A. hybridus and A. deflexus had the highest crude fibre content. NPK and PM favoured growth and yield of the Amaranthus species but influenced proximate composition differently. Stephen Oyedeji, David Adedayo Animasaun, Abdullahi Ajibola Bello, and Oludare Oladipo Agboola Copyright © 2014 Stephen Oyedeji et al. All rights reserved. Morphobiochemical Variability and Selection Strategies for the Germplasm of Dactylorhiza hatagirea (D. Don) Soo: An Endangered Medicinal Orchid Sun, 05 Jan 2014 14:08:25 +0000 http://www.hindawi.com/journals/jb/2014/869167/ Dactylorhiza hatagirea (D. Don) Soo (Orchidaceae) is an important endangered medicinal herb, distributed in subalpine to alpine regions of the Himalayas. Its tubers are important constituents of many medicines and health tonics. Overexploitation for medicinal uses has decreased availability in natural habitats and this species has been enlisted as endangered, making conservation and cultivation studies necessary. Variability studies may serve as an important tool for effective conservation and for a crop improvement program. Therefore, natural populations of D. hatagirea were analyzed for variability on the basis of morphological, biochemical, and isoenzyme patterns. The studied populations were grouped into two clusters. Existing variability among different populations opens up new areas for conservation and perspectives for a genetic improvement program for D. hatagirea. R. S. Chauhan, M. C. Nautiyal, R. K. Vashistha, and P. Prasad Copyright © 2014 R. S. Chauhan et al. All rights reserved. Chromium (VI) Induced Biochemical Changes and Gum Content in Cluster Bean (Cyamopsis tetragonoloba L.) at Different Developmental Stages Sun, 22 Dec 2013 10:42:30 +0000 http://www.hindawi.com/journals/jb/2013/578627/ Chromium (Cr) contamination by various industries and other activities is known to inhibit plants growth and development. The present study was conducted using pot experiments in a net house to determine the effect of Cr (VI) on biochemical parameters such as photosynthetic pigments, reducing sugars, and important minerals at different stages of growth in leaves, stem, and roots of clusterbean, a multipurpose fodder crop including a source of guar gum. Guar gum content was estimated in seeds at maturity. All biochemical contents showed a great variation with respect to increase in Cr concentration at different stages of growth. The levels of K, Fe, and Zn decreased, while Cr and Na content increased with increase in Cr concentration. Cr induced toxicity in clusterbean appears at 0.5 mg Cr (VI) Kg−1 soil with maximum inhibitory effect at 2 mg Cr (VI) Kg−1 soil, where impaired sugar supply resulted in decreased guar gum synthesis and altered micronutrient content. The study reveals the possible role of these biochemical parameters in decreasing plant growth and development under heavy metal stress. Punesh Sangwan, Vinod Kumar, R. S. Khatri, and U. N. Joshi Copyright © 2013 Punesh Sangwan et al. All rights reserved. Indole-3-Acetic Acid, Polyamines, and Phenols in Hardwood Cuttings of Recalcitrant-to-Root Wild Grapes Native to East Asia: Vitis davidii and Vitis kiusiana Wed, 27 Nov 2013 13:41:10 +0000 http://www.hindawi.com/journals/jb/2013/819531/ Levels of indole-3-acetic acid (IAA), free, conjugated, and bound polyamines (PAs), and phenols were estimated in the basal portion of hardwood cuttings of Vitis davidii and V. kiusiana in relation to rooting and compared with Vitis labruscana Bailey cv. Campbell Early. A high rate of root formation was observed in ‘Campbell Early’ cuttings 60 days after planting. However, none of the V. davidii and V. kiusiana cuttings formed roots. An increase in IAA contents was observed in ‘Campbell Early’ cuttings, but not in V. davidii and V. kiusiana, 60 days after planting. The content of free, conjugated, and bound PAs was either constant or decreased in ‘Campbell Early’ cuttings during planting and was especially decreased in conjugated putrescine and spermidine. An increase in free and conjugated putrescine was observed after planting in V. kiusiana cuttings. In the cuttings of V. davidii, only bound spermine increased after planting. The content of total phenols, orthodiphenols, total catechins, and gallocatechin derivatives decreased after planting in ‘Campbell Early’ cuttings. Orthodiphenols and total catechin contents increased in the cuttings of V. kiusiana, and gallocatechin derivatives increased in V. davidii. The relationships between these endogenous factors and the recalcitrant-to-root features of V. davidii and V. kiusiana cuttings are discussed. Shuji Shiozaki, Masahiro Makibuchi, and Tsuneo Ogata Copyright © 2013 Shuji Shiozaki et al. All rights reserved. Ethnobotany and Ethnomedicinal Uses, Chromosomal Status and Natural Propagation of Some Plants of Lahaul-Spiti and Adjoining Hills Wed, 13 Nov 2013 13:31:48 +0000 http://www.hindawi.com/journals/jb/2013/248943/ The present study documented the ethnobotanical and medicinal uses of plants from an ecologically fragile cold desert area of Lahaul-Spiti (Himachal Pradesh, India). Local people use plants for curing the stomach troubles, pain reliever, cough, gastric disorders, and aphrodisiac and other household purposes. In addition, chromosome numbers, male meiosis, and natural propagation were also investigated in these ethnobotanically used plants. Present investigations also form the basis for exploitation of intraspecific chromosomal variation/new cytotypes recorded in some of the presently studied species to detect biochemical diversity in the medicinally important plants. For documentation of ethnobotanical information, personal observations and interviews were conducted with medicine men, hakims, farmers, shepherds, local healers, and old aged people. This study identified 40 plant species under 33 genera belonging to 17 families which have been used locally for curing various diseases and other purposes. All the chromosome counts are new to the study area. On worldwide basis, meiotic chromosome counts of and in Rosularia alpestris and Corydalis govaniana, respectively, are the first ever reports. The present study indicates that the people of the area possess good knowledge about the different uses of plants in the area. It has been noticed that due to the lack of interest among younger generations in the preservation of invaluable ethnic knowledge, there is every possible chance of losing such a rich heritage of knowledge. It is very urgent to conserve such invaluable ethnic knowledge before it gets lost. Puneet Kumar and Vijay Kumar Singhal Copyright © 2013 Puneet Kumar and Vijay Kumar Singhal. All rights reserved. Induction of a bZIP Type Transcription Factor and Amino Acid Catabolism-Related Genes in Soybean Seedling in Response to Starvation Stress Sun, 10 Nov 2013 10:57:02 +0000 http://www.hindawi.com/journals/jb/2013/935479/ To address roles of bZIP transcription factors on regulation of amino acid catabolism under autophagy-induced plant cells, we examined the effect of nutrient starvation on the expression of low energy stress-related transcription factor homologs, GmbZIP53A and GmbZIP53B, and amino acid catabolism-related genes in soybean (Glycine max (L.) Merr.). Sucrose starvation treatment significantly enhanced the expressions of GmbZIP53A, but not GmbZIP53B asparagine synthase (GmASN1), proline dehydrogenase1 (GmProDH), and branched chain amino acid transaminase 3 (GmBCAT3). GmbZIP53-related immunoreactive signals were upregulated under severe starvation with sucrose starvation and protease inhibitors, while 3% sucrose and sucrose starvation had no or marginal effects on the signal. Profiles of induction of GmASN1, GmProDH and GmBCAT3 under various nutrient conditions were consistent with the profiles of GmbZIP53 protein levels but not with those of GmbZIP mRNA levels. These results indicate that GmbZIP53 proteins levels are regulated by posttranslational mechanism in response to severe starvation stress and that the increased protein of GmbZIP53 under severe starvation accelerates transcriptional induction of GmASN1, GmProDH, and GmBCAT3. Furthermore, it is conceivable that decrease of branched chain amino acid level by the BCAT-mediated degradation eventually enhances autophagy under severe starvation. Takashi Yuasa, Yuri Nagasawa, Katsumasa Osanai, Ayami Kaneko, Daichi Tajima, Nang Myint Phyu Sin Htwe, Yushi Ishibashi, and Mari Iwaya-Inoue Copyright © 2013 Takashi Yuasa et al. All rights reserved. Leaf Epidermal Micromorphology of Portulaca L. Species Found in Vadodara, Gujarat, India Thu, 07 Nov 2013 09:52:47 +0000 http://www.hindawi.com/journals/jb/2013/368238/ Micromorphology of three species of Portulaca was carried out with the help of light microscopy to determine variations within the species which would aid in correct identification of the plants. Epidermal cells are polygonal with sinuous anticlinal walls in all the three species. Length of epidermal cells of P. grandiflora Hook. is higher than P. oleracea Linn. and P. quadrifida Linn. The leaves of P. quadrifida are epistomatic while the remaining species are amphistomatic with paracytic stomata in all the three species. Mean stomatal index and stomatal frequency are more in P. quadrifida while the mean size of stomata (both length and width) is larger in P. grandiflora for both adaxial and abaxial surfaces. Based on the diagnostic features, an artificial indented key is prepared. Archana Srivastava, Aruna Girish Joshi, and Vinay Madhukar Raole Copyright © 2013 Archana Srivastava et al. All rights reserved. Study of Flowering Pattern in Setaria viridis, a Proposed Model Species for C4 Photosynthesis Research Wed, 09 Oct 2013 17:46:41 +0000 http://www.hindawi.com/journals/jb/2013/592429/ Green foxtail millet (Setaria viridis) has NADP-ME type of C4 photosynthesis. Because of its short life cycle, small genome size of ~515 Mb, small plant stature, high number of seed set, simple growth requirements, and wide adaptability, this diploid () weed is proposed to be a model species for the study of C4 photosynthesis. It is also a representative of bioenergy grasses and a model for genetic study of invasive weeds. Despite having all traits of a model species, it is difficult to cross-pollinate because its flowering behavior is not well studied. We used time lapse digital recording to study the flowering time and pattern along a single panicle. We found that flowering in Setaria was triggered by the darkness of the night and when the temperature was lower than 35°C. The anthesis of all the spikelets in a panicle took up-to three nights flowering from 9:30 pm to 10:00 am in the morning. Each spikelet has three phases of anthesis during which pollination occurs. A spikelet remains open for less than three hours. The pollination time for each spikelet is less than 60 minutes. Information from this study will facilitate the geneticists and plant breeders to plan for efficient crossing of Setaria. Govinda Rizal, Kelvin Acebron, Reychelle Mogul, Shanta Karki, Nikki Larazo, and William Paul Quick Copyright © 2013 Govinda Rizal et al. All rights reserved. Responses of Green Leaves and Green Pseudobulbs of CAM Orchid Cattleya laeliocattleya Aloha Case to Drought Stress Tue, 16 Jul 2013 11:31:15 +0000 http://www.hindawi.com/journals/jb/2013/710539/ This study examined the responses of green leaves (GL) and green pseudobulbs (GPSB) of CAM orchid Cattleya laeliocattleya Aloha Case to drought stress. After being subjected to drought stress, the decrease in water content (WC) was much greater in GPSB than in GL, indicating that GPSB facilitated a slow reduction in the WC of GL. This finding was further supported by the result of relative water content (RWC) of GL, which started to decrease only after 3 weeks of drought stress. Decreases of midday ratios of GL occurred in all plants. However, the degrees of decrease were much greater in drought-stressed GL than in well-watered GL. Reduced ratio (<0.8) at early morning was observed in drought-stressed GL after 3 weeks of treatments. Decreases in total chlorophyll (Chl) content, electron transport rate (ETR), photochemical quenching, qP, and nonphotochemical quenching, qN, were severer in GPSB than in GL after drought treatment. CAM acidity was significantly lower in both GL and GPSB after 2 weeks of drought treatment compared to well-watered plants. However, decrease of CAM acidity was smaller in GL than in GPSB. These results suggest that both GL and GPSB of CAM orchid Cattleya plantswere susceptible to drought stress. Jie He, Hazelman Norhafis, and Lin Qin Copyright © 2013 Jie He et al. All rights reserved. Phenology of Some Phanerogams (Trees and Shrubs) of Northwestern Punjab, India Tue, 25 Jun 2013 16:56:30 +0000 http://www.hindawi.com/journals/jb/2013/712405/ Plants perform various vegetative and reproductive functions throughout the year in order to persist in their habitats. The study of these events including their timing and how the environment influences the timing of these events is known as phenology. This study of the timing of seasonal biological activities of plants is very important to know about plant’s survival and its reproductive success. The variation in the phenological activities is due to change in different abiotic conditions. This paper deals with the study of phenological activities like bud formation, flowering time, fruiting time, and seed formation for some leguminous plants of Amritsar, Punjab (a state in the northwest of India) for three consecutive years from 2009 till 2011. Gurveen Kaur, Bhupinder Pal Singh, and Avinash Kaur Nagpal Copyright © 2013 Gurveen Kaur et al. All rights reserved. A Comparative Analysis of the Mechanical Role of Leaf Sheaths of Poaceae, Juncaceae, and Cyperaceae Thu, 11 Apr 2013 11:44:56 +0000 http://www.hindawi.com/journals/jb/2013/690549/ Similarities in structural organization of the culm in Poaceae, Juncaceae, and Cyperaceae such as leaf sheaths and the presence of intercalary meristems at every node suggest the same mechanical properties and, accordingly, the same functionality. Meristems are zones of tissue formation, which constitute areas of weakness along the entire culm and provide the basis for rapid shoot elongation. Leaf sheaths clasp the culm preventing the shoot from breaking, ensuring the rigidity to grow erectly and to avoid damage of the meristematic tissue. The mechanical influence of leaf sheaths was investigated in members of Poaceae, Juncaceae, and Cyperaceae in the flowering stage. Mechanical properties of Poa araratica, Bromus erectus, Arrhenatherum elatius (Poaceae), Luzula nivea (Juncaceae), and Carex arctata (Cyperaceae) were determined in three-point bending before and after the removal of leaf sheaths. The presence of leaf sheaths results in smoothing the distribution of flexural rigidity and therefore avoids stress peaks. The achieved maxima of relative contribution of leaf sheaths to entire flexural rigidity ranged from 55% up to 81% for Poaceae, 72% for C. arctata, and 40% for L. nivea. Across the investigated families, the mechanical role of leaf sheaths could be verified as essential for culm stability during development and beyond. Andreas Kempe, Martin Sommer, and Christoph Neinhuis Copyright © 2013 Andreas Kempe et al. All rights reserved. Seed and Embryo Germination in Ardisia crenata Tue, 04 Dec 2012 15:09:15 +0000 http://www.hindawi.com/journals/jb/2012/679765/ Ardisia crenata is an evergreen shrub with attractive bright red berries. Although this species is usually propagated by seed, the seeds take a long time to germinate with conventional sowing methods. We investigated the germination capacity of seeds and embryos collected in different months and the effects of seed storage conditions, germination temperature, water permeability of the seed coat, and the endosperm on seed germination. Seeds and embryos collected in late September or later showed good germination rates. Seeds germinated more rapidly after longer periods of storage at low temperature (approximately 5°C), and those stored in dry conditions showed lower emergence frequency than those stored in wet conditions. Seeds germinated at 15–30°C, but not at 5–10°C. Removal of the seed coat enhanced water uptake and seed germination. Seeds with various proportions of the removed seed coat were sown on a medium supplemented with sucrose. The germination frequency increased as the size of the remaining endosperm decreased. However, the opposite results were obtained when seeds were sown on a medium without sucrose. We concluded that the optimal temperature of 25°C is the most critical factor for seed germination in A. crenata. Takahiro Tezuka, Hisa Yokoyama, Hideyuki Tanaka, Shuji Shiozaki, and Masayuki Oda Copyright © 2012 Takahiro Tezuka et al. All rights reserved. Legacy and Emerging Contaminants in Plants: From the Gene to the Field Wed, 28 Nov 2012 14:23:40 +0000 http://www.hindawi.com/journals/jb/2012/382717/ Conceição Santos, Helena Oliveira, Joanna Deckert, and Jason C. White Copyright © 2012 Conceição Santos et al. All rights reserved. The Evolutionary Dynamics of Apomixis in Ferns: A Case Study from Polystichoid Ferns Mon, 05 Nov 2012 16:34:06 +0000 http://www.hindawi.com/journals/jb/2012/510478/ The disparate distribution of apomixis between the major plant lineages is arguably one of the most paradoxical phenomena in plant evolution. Ferns are particularly interesting for addressing this issue because apomixis is more frequent than in any other group of plants. Here, we use a phylogenetic framework to explore some aspects of the evolution of apomixis in ferns and in particular in the polystichoid ferns. Our findings indicate that apomixis evolved several times independently in three different clades of polystichoid ferns. A lineage-wide perspective across ferns indicates a correlation between apomixis and the species richness of lineages; however BiSSE tests did not recover evidence for a correlation of apomixis and diversification rates. Instead, evidence was recovered supporting an association between the establishment of apomixis and reticulate evolution, especially in the establishment of triploid hybrids. Diversification time estimates supported the hypothesis of short living apomictic lineages and indicated a link between the establishment of apomixis and the strengthening of the monsoons caused by the lifting of the Qinghai-Tibetan plateau. In general our results supported the hypothesis for the rare establishment of apomictic lineages, high extinction risks, and low speciation rates. Hong-Mei Liu, Robert J. Dyer, Zhi-You Guo, Zhen Meng, Jian-Hui Li, and Harald Schneider Copyright © 2012 Hong-Mei Liu et al. All rights reserved. Boron-Mediated Plant Somatic Embryogenesis: A Provocative Model Tue, 02 Oct 2012 10:03:20 +0000 http://www.hindawi.com/journals/jb/2012/375829/ A central question in plant regeneration biology concerns the primary driving forces invoking the acquisition of somatic embryogenesis. Recently, the role of micronutrient boron (B) in the initiation and perpetuation of embryogenesis has drawn considerable attention within the scientific community. This interest may be due in part to the bewildering observation that the system-wide induction of embryogenic potential significantly varied in response to a minimal to optimal supply of B (minimal ≤ 0.1 mM, optimal = 0.1 mM). At the cellular level, certain channel proteins and cell wall-related proteins important for the induction of embryogenesis have been shown to be transcriptionally upregulated in response to minimal B supply suggesting the vital role of B in the induction of embryogenesis. At the molecular level, minimal to no B supply increased the endogenous level of auxin, which subsequently influenced the auxin-inducible somatic embryogenesis receptor kinases, suggesting the role of B in the induction of embryogenesis. Also, minimal B concentration may “turn on” other genetic and/or cellular transfactors reported earlier to be essential for cell-restructuring and induction of embryogenesis. In this paper, both the direct and indirect roles of B in the induction of somatic embryogenesis are highlighted and suggested for future validation. Dhananjay K. Pandey, Arvind K. Singh, and Bhupendra Chaudhary Copyright © 2012 Dhananjay K. Pandey et al. All rights reserved. Saline Agriculture in the 21st Century: Using Salt Contaminated Resources to Cope Food Requirements Thu, 09 Aug 2012 09:41:23 +0000 http://www.hindawi.com/journals/jb/2012/310705/ With the continue increase of the world population the requirements for food, freshwater, and fuel are bigger every day. This way an urgent necessity to develop, create, and practice a new type of agriculture, which has to be environmentally sustainable and adequate to the soils, is arising. Among the stresses in plant agriculture worldwide, the increase of soil salinity is considered the major stress. This is particularly emerging in developing countries that present the highest population growth rates, and often the high rates of soil degradation. Therefore, salt-tolerant plants provide a sensible alternative for many developing countries. These plants have the capacity to grow using land and water unsuitable for conventional crops producing food, fuel, fodder, fibber, resin, essential oils, and pharmaceutical products. In addition to their production capabilities they can be used simultaneously for landscape reintegration and soil rehabilitation. This review will cover important subjects concerning saline agriculture and the crop potential of halophytes to use salt-contaminated resources to manage food requirements. Bruno Ladeiro Copyright © 2012 Bruno Ladeiro. All rights reserved. Phytotoxicity by Lead as Heavy Metal Focus on Oxidative Stress Thu, 19 Jul 2012 13:49:38 +0000 http://www.hindawi.com/journals/jb/2012/369572/ In the recent years, search for better quality of life in urban areas has been provoking an increase in urban agriculture. However, this new way of agriculture can bring risks to human health since this land is highly contaminated, due to anthropogenic activities. This way, lead (Pb) phytotoxicity approach must be taken into consideration since it can be prejudicial to human health through food chain. Pb is a common environmental contaminant, which originate numerous disturbances in plant physiological processes due to the bioacummulation of this metal pollutant in plant tissues. This review, focus on the uptake and interaction of lead by plants and how it can be introduced in food chain. Special attention was taken to address the oxidative stress by lead regarding the effects produced in plant physiological and biochemical processes. Furthermore, the antioxidant defence system was taken into consideration. Phytoremediation is applied on site or chronic polluted soils. This emerging technique is useful to bioaccumulate, degrade or decrease risks associated with contaminants in soils, water or air through the use of hyperaccumulaters. In addition, the impact of nanoparticles in plant science was also focused in this article since some improving properties in plants have been increasingly investigated. Sónia Pinho and Bruno Ladeiro Copyright © 2012 Sónia Pinho and Bruno Ladeiro. All rights reserved. Aluminium Toxicity Targets in Plants Mon, 02 Jul 2012 08:11:53 +0000 http://www.hindawi.com/journals/jb/2012/219462/ Aluminium (Al) is the third most abundant metallic element in soil but becomes available to plants only when the soil pH drops below 5.5. At those conditions, plants present several signals of Al toxicity. As reported by literature, major consequences of Al exposure are the decrease of plant production and the inhibition of root growth. The root growth inhibition may be directly/indirectly responsible for the loss of plant production. In this paper the most remarkable symptoms of Al toxicity in plants and the latest findings in this area are addressed. Root growth inhibition, ROS production, alterations on root cell wall and plasma membrane, nutrient unbalances, callose accumulation, and disturbance of cytoplasmic Ca2+ homeostasis, among other signals of Al toxicity are discussed, and, when possible, the behavior of Al-tolerant versus Al-sensitive genotypes under Al is compared. Sónia Silva Copyright © 2012 Sónia Silva. All rights reserved. Environmental Nanoparticles Interactions with Plants: Morphological, Physiological, and Genotoxic Aspects Sun, 17 Jun 2012 17:10:08 +0000 http://www.hindawi.com/journals/jb/2012/751686/ Nanoparticles (NPs) are characterized by their small size (less than 100 nm) and large surface area, which confer specific physicochemical properties as strength, electrical, and optical features. NPs can be derived from natural or anthropic sources, such as engineered or unwanted/incidental NPs. The composition, dimension, and morphology of engineered NPs enable their use in a variety of areas, such as electronic, biomedical, pharmaceutical, cosmetic, energy, environmental, catalysis, and materials science. As nanotechnology is an innovative and scientific growth area with an exponential production, more information is needed concerning the impacts of these nanomaterials (NMs) in the environment and, particularly, in animals/humans health and in plants performance. So, research on NPs as emerging contaminants is therefore a new field in environmental health. This minireview describes, briefly, the NPs characterization and their occurrence in the environment stating air, water, and soil. Finally, particular emphasis is given to the interaction of NPs with plants at different levels: morphology, physiology, and genotoxicity. By analyzing this compiled information, it is evident that research on NPs phytotoxicity is in the beginning, and more comprehensive studies are needed not only on NPs cytotoxicity and genotoxicity but also on the best and the most reliable methods of assessing NPs toxicity. C. Remédios, F. Rosário, and V. Bastos Copyright © 2012 C. Remédios et al. All rights reserved. Roles of Protein Synthesis Elongation Factor EF-Tu in Heat Tolerance in Plants Sun, 03 Jun 2012 18:09:01 +0000 http://www.hindawi.com/journals/jb/2012/835836/ EF-Tu proteins of plastids, mitochondria, and the cytosolic counterpart EF-1α in plants, as well as EF-Tu proteins of bacteria, are highly conserved and multifunctional. The functions of EF-Tu include transporting the aminoacyl-tRNA complex to the A site of the ribosome during protein biosynthesis; chaperone activity in protecting other proteins from aggregation caused by environmental stresses, facilitating renaturation of proteins when conditions return to normal; displaying a protein disulfide isomerase activity; participating in the degradation of N-terminally blocked proteins by the proteasome; eliciting innate immunity and triggering resistance to pathogenic bacteria in plants; participating in transcription when an E. coli host is infected with phages. EF-Tu genes are upregulated by abiotic stresses in plants, and EF-Tu plays important role in stress responses. Expression of a plant EF-Tu gene confers heat tolerance in E. coli, maize knock-out EF-Tu null mutants are heat susceptible, and over-expression of an EF-Tu gene improves heat tolerance in crop plants. This review paper summarizes the current knowledge of EF-Tu proteins in stress responses in plants and progress on application of EF-Tu for developing crop varieties tolerant to abiotic stresses, such as high temperatures. Jianming Fu, Ivana Momčilović, and P. V. Vara Prasad Copyright © 2012 Jianming Fu et al. All rights reserved. Adaptation to High Temperature and Water Deficit in the Common Bean (Phaseolus vulgaris L.) during the Reproductive Period Mon, 28 May 2012 11:49:02 +0000 http://www.hindawi.com/journals/jb/2012/803413/ This paper reviews the adaption to heat and drought stresses in Phaseolus vulgaris, a grain and vegetable crop widely grown in both the Old and New World. Substantial genotypic differences are found in morphophysiological characteristics such as phenology, partitioning, plant-water relations, photosynthetic parameters, and shoot growth, which are related to reproductive responses. The associations between (a) days to podding and leaf water content and (b) the number of pods per plant and seed yield are consistent across different environments and experiments. Leaf water content is maintained by reductions in leaf water potential and shoot extension in response to heat and drought stress. Heat-tolerant cultivars have higher biomass allocation to pods and higher pod set in branches. These traits can be used as a marker to screen germplasm for heat and drought tolerance. In this paper, we briefly review the results of our studies carried out on heat and drought tolerance in the common bean at the Tropical Agriculture Research Front, Ishigaki, Japan. Hide Omae, Ashok Kumar, and Mariko Shono Copyright © 2012 Hide Omae et al. All rights reserved. Phytotoxicity of Mercury in Plants: A Review Sun, 20 May 2012 10:16:15 +0000 http://www.hindawi.com/journals/jb/2012/848614/ With the advent of the industrial revolution, heavy metal contamination has become an ever increasing concern. Thus, it is of major importance to understand the extent of the toxicity in plants and animals and the consequences from the ingestion of contaminated food. Hg is easily modified into several oxidation states, and it can be spread in many ecosystems. Due to the recurrence of Hg pollution and due to the lack of knowledge about the effects of this heavy metal in plants, the aim of the present text is to provide a comprehensive review of the literature regarding Hg phytotoxicity. Raquel Azevedo and Eleazar Rodriguez Copyright © 2012 Raquel Azevedo and Eleazar Rodriguez. All rights reserved. Chromium as an Environmental Pollutant: Insights on Induced Plant Toxicity Sun, 20 May 2012 10:14:22 +0000 http://www.hindawi.com/journals/jb/2012/375843/ In the past decades the increased use of chromium (Cr) in several anthropogenic activities and consequent contamination of soil and water have become an increasing concern. Cr exists in several oxidation states but the most stable and common forms are Cr(0), Cr(III) and Cr(VI) species. Cr toxicity in plants depends on its valence state. Cr(VI) as being highly mobile is toxic, while Cr(III) as less mobile is less toxic. Cr is taken up by plants through carriers of essential ions such as sulphate. Cr uptake, translocation, and accumulation depend on its speciation, which also conditions its toxicity to plants. Symptoms of Cr toxicity in plants are diverse and include decrease of seed germination, reduction of growth, decrease of yield, inhibition of enzymatic activities, impairment of photosynthesis, nutrient and oxidative imbalances, and mutagenesis. Helena Oliveira Copyright © 2012 Helena Oliveira. All rights reserved. Karyomorphological Studies in Some Species of Parnassia L. (Saxifragaceae s.l.) in East Asia and Intraspecific Polyploidy of P. palustris L. Tue, 15 May 2012 10:37:32 +0000 http://www.hindawi.com/journals/jb/2012/874256/ Karyomorphological information is one of the most important characters for cytotaxonomy. We described karyomorphology of 14 species of Parnassia in East Asia. They had commonly the resting chromosomes of the simple chromocenter type and the mitotic prophase chromosomes of the proximal type. The somatic chromosome number of 2𝑛=14 was shown in three species, that of 2𝑛=18 was shown in six species, that of 2𝑛=18 or 36 was shown in two species, that of 2𝑛=32 was shown in one species, that of 2𝑛=36 or 36+1∼8 s was shown in one species, and that of 2𝑛=18, 27, 36 or 45 was shown in one species. They were commonly monomodal (gradual) decrease in length from the largest to the smallest chromosomes. However, their absolute chromosome sizes were different from each other. Average chromosome sizes were recognized as three types small (1.21 μm), medium (1.7–2.36 μm), and large (3.1–3.75 μm). Parnassia palustris showed four cytotypes that could be likely cytogeographically correlated with habitats, polyploidy, and sizes of pollen grains. Tsuneo Funamoto and Katsuhiko Kondo Copyright © 2012 Tsuneo Funamoto and Katsuhiko Kondo. All rights reserved. Parameters Symptomatic for Boron Toxicity in Leaves of Tomato Plants Wed, 09 May 2012 14:28:27 +0000 http://www.hindawi.com/journals/jb/2012/726206/ The incidence of boron (B) toxicity has risen in areas of intensive agriculture close to the Mediterranean sea. The objective of this research was to study the how B toxicity (0.5 and 2 mM B) affects the time course of different indicators of abiotic stress in leaves of two tomato genotypes having different sensitivity to B toxicity (cv. Kosaco and cv. Josefina). Under the treatments of 0.5 and 2 mM B, the tomato plants showed a loss of biomass and foliar area. At the same time, in the leaves of both cultivars, the B concentration increased rapidly from the first day of the experiment. These results were more pronounced in the cv. Josefina, indicating greater sensitivity than in cv. Kosaco with respect to excessive B in the environment. The levels of O2•− and anthocyanins presented a higher correlation coefficient (𝑟>0.9) than did the levels of B in the leaf, followed by other indicators of stress, such as GPX, chlorophyll b and proline (𝑟>0.8). Our results indicate that these parameters could be used to evaluate the stress level as well as to develop models that could help prevent the damage inflicted by B toxicity in tomato plants. Luis M. Cervilla, Begoña Blasco, Juan J. Rios, Miguel A. Rosales, Eva Sánchez-Rodríguez, Maria M. Rubio-Wilhelmi, Luis Romero, and Juan M. Ruiz Copyright © 2012 Luis M. Cervilla et al. All rights reserved.