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Many ant partners of tropical ant-plants prune the leaves and shoot tips of other plants growing around their hosts. According to the hypothesis proposed by Davidson et al. (Ecology 69:801–808), this specialized behaviour not only protects the host plants against overgrowth, but it also conveys a direct benefit to the ant colony as it removes contact points to the neighbouring vegetation where invasions of enemy ants could occur. Here we test this hypothesis by comparing pruning intensity in five closely related Crematogaster (subgenus Decacrema) plant-ant species (and one species of Technomyrmex) that differ in their exposure to competition by other ants. Pruning intensity was quantified by measuring the area loss of paper tape pieces wrapped around the stems of Macaranga host plants. All Crematogaster (Decacrema) ants tested but not Technomyrmex sp. pruned, but the intensity of the behaviour varied strongly between and within species. Pruning was significantly weaker in the three tested Crematogaster species inhabiting Macaranga host plants with a slippery, waxy stem surface, which functions as a mechanical barrier protecting the specific ant partners against generalist competitors. Pruning was generally stronger on more densely ant-populated trees. Even though the number of ants per twig length was lower in associations of ants with glaucous Macaranga hosts, only part of the variation of pruning activity could be explained by "ant density". When corrected for ant density, "wax-running" Crematogaster (Decacrema) ants still pruned more weakly than their congeners inhabiting non-glaucous Macaranga hosts. Pruning is obviously most important when an ant-plant is potentially accessible to intruders, but less necessary when the ant colony is isolated by a protective wax barrier. Our results support the hypothesis that "selfish" defence against invasions is the major selective pressure that has led to the development and maintenance of pruning behaviour in weakly competitive plant-ants. [ABSTRACT FROM AUTHOR]

Plants produce thousands of phenolic and polyphenolic compounds as secondary metabolites. They are essential to the physiology of plants being involved in diverse functions such as lignification and structure, pigmentation, pollination, allelopathy, pathogen and predator resistance and growth. Approximately 8000 have been described to date, major classes being flavonoids, flavones, flavan-3ols, flavanones and anthocyanins. They can be isolated from biomass waste and cultivated and spontaneous plants by biorefining and used for their biological properties in different fields. In this paper some examples of uses such as: modulation agents of carbohydrates metabolism in diabetes and alcoholic fermentation, agents for regulation of physiological process in plants (germination, plant propagation and cultivation, tissue culture, bioremediation), modulation agents of metabolic processes in microorganisms (antifungal and antibacterial properties, antioxidants), models to study the influence of stress factors (hydrogen peroxide oxidation and UV irradiation and life span regulation), and carbon sources as substrates in medium cultivation of microorganisms, are presented. [ABSTRACT FROM AUTHOR]

Bas Bargmann, a plant scientist, discusses his interest in plant science and his decision to pursue a career in research. He emphasizes the importance of plants in providing essential elements for society, such as food and medicine, and expresses his fascination with the physiology and development of plants. Bargmann also highlights his motivation in working with students and helping them conduct research. He refrains from naming specific role models but mentions the qualities of enthusiasm, generosity, and dedication that he admires in others. Additionally, Bargmann mentions his favorite recent paper in the field of plant science, which explores single-cell proteomics in Arabidopsis root cell types. He concludes by mentioning his love for various plants, including cassava, and his excitement to work with them in his research. [Extracted from the article]

Summary: Plant Ecophysiology is the study on how Plant Physiology is modulated by the environment. This discipline could have benefited greatly from the development of the different 'omic' technologies (from genomics to metabolomics). Instead, the overall impression is that ecophysiology and 'omics' have developed mostly independent each other. Here we provide a literature analysis over the past 20 years which fully confirms this view. Then, we review a few examples of studies in which ecophysiology and 'omics' studies have combined to different extents to illustrate the potential benefits from their mutualistic interaction. In addition, we debate on the possibilities of working with plants other than Arabidopsis, which is illustrated with some examples of fascinating plants from extreme environments of the world, what we call the 'sherplants'. Finally, we raise a call to both communities (ecophysiology and 'omics') to integrate these disciplines to enter an 'ecophysiolomics era' to maximize our understanding about plant mechanisms from a multidisciplinary approach. Significance Statement: In this work we analyzed the relationship between the 'omic' technologies and plant ecophysiology. Literature data show that they developed mostly independent each other over the last 20 years. This fact promotes separated communities in each field losing the potential benefits from their mutualistic interaction. Here, we raise a call to both communities to integrate these disciplines to maximize our understanding about plant mechanisms from a multidisciplinary approach. [ABSTRACT FROM AUTHOR]

It has been observed from field work that the aquatic moss Eurhynchium riparioides is capable of living below the discharge from a coal washery effluent. The first paper describes what effect suspended coal particles have upon the gametophyte plant and it was observed that the moss plant can still survive even in levels of coal dust as high as 5000 mg/l. The second paper now describes what effect coal dust has on the reproducing powers of E. riparioides. The percentage germination of the spores of E. riparioides is reduced by 42% in the presence of 5000 mg/l of suspended coal particles, but with decrease in coal dust concentration there is an increase in the amount of germination. The effect of suspended coal dust on the regeneration from detached apical tips of E. riparioides is also discussed, and it is seen that rhizoidal growth occurs in every concentration of coal dust including 5000 mg/l, although the development of new side shoots is only observed in concentrations below 500 mg/l. [ABSTRACT FROM AUTHOR]

The present paper is concerned with a study of the uptake and metabolism of sulphur and related problems in deseeded wheat plants. For this purpose tracer techniques in combination with paper chromatography of the amino acids and determinations of the Kjeldahl nitrogen of different fractions have been applied. A critical discussion is given of the isotope methods used and possible errors involved in them. There is a general difference in the growth of roots and shoots, perhaps connected with the deseeding procedure. This is illustrated by data from plants on complete nutrient solutions as well as by changes in fresh weight relations and nitrogen metabolism induced during conditions of sulphur deficiency. A comparison of the quantitative changes in insoluble nitrogen and sulphur of the shoots during - S conditions leads to the conclusion, that at least two different protein types are present. High sulphur proteiu is broken down whereas low sulphur protein is still synthesized to some extent. The amino acid composition of the plants has been investigated and is tabulated. - In all fractions both the methionine derivatives and eyst(e)ine become radioactive at the same time when the plants are allowed to absorb S35. A translocation of sulphur takes place from the old to the young parts of the shoot during development; nevertheless symptoms of S deficiency are obtained before the sulphate reserve of the plant is totally exhausted. A back transport from the shoots to the roots can also be established as well as a leakage into the solutions. Sulphate uptake is independent of the pH of the solution. The rate of the uptake of radiosulphate is higher during the first minutes than after some time has elapsed. The possible significance of this is discussed in connection with current views on ion uptake. [ABSTRACT FROM AUTHOR]

In a previous paper (B) a torsion balance method for transpiration measurements in excised leaves or shootshas been described, and values obtained in experiments with Vaccinium myrtillus cited. In the present paper the results of further measurements by the same method are reported. Two more species of Vaccinium have been fairly well investigated, viz.. V. uliginosum and V. vitis-idaea. Besides, less extensive series of experiments have been made with samples of the following species: Alchemilla alpina, A. glabru, A. glomerulans,, Antennaria dioica, Calluna vulgaris, Empetrum hermaphroditum, Mianthemum bifoiumi, Pingucicula vulgaris,. Potentilla palustris. Rubuns Chamaemorus, Salix herbacea, Saussurea alpina, Saxifraga aizoides, Sibbaldia procumbens, and Viola palustris. In many cases samples of the same species were taken from several ecologically distinct localities. The course of the transpiration decline curves obtained in these experiments is described elsewhere (7). In the present paper the transpiration values calculated from the curves are reported and their significance discussed. [ABSTRACT FROM AUTHOR]

Cytokinins in cotton fruits were detected by the soybean callus bioassay on the 1st day after anthesis. Peak cytokinin activity occurred from the 4th to the 9th day and then declined to little or none by the 18th day after anthesis. The principal cytokinin remained below Rf 0.2, when chromatographed on paper with water-saturated sec-butanol, and predominated throughout the period of cytokinin activity. Another cytokinin, migrating to Rf 0.8, remained less active. [ABSTRACT FROM AUTHOR]

With the global climate anomalies and the destruction of ecological balance, the water shortage has become a serious ecological problem facing all mankind, and drought has become a key factor restricting the development of agricultural production. Therefore, it is essential to study the drought tolerance of crops. Based on previous studies, we reviewed the effects of drought stress on plant morphology and physiology, including the changes of external morphology and internal structure of root, stem, and leaf, the effects of drought stress on osmotic regulation substances, drought-induced proteins, and active oxygen metabolism of plants. In this paper, the main drought stress signals and signal transduction pathways in plants are described, and the functional genes and regulatory genes related to drought stress are listed, respectively. We summarize the above aspects to provide valuable background knowledge and theoretical basis for future agriculture, forestry breeding, and cultivation. [ABSTRACT FROM AUTHOR]

Plant phenotyping is a central task in crop science and plant breeding. It involves measuring plant traits to describe the anatomy and physiology of plants and is used for deriving traits and evaluating plant performance. Traditional methods for phenotyping are often time-consuming operations involving substantial manual labor. The availability of 3D sensor data of plants obtained from laser scanners or modern depth cameras offers the potential to automate several of these phenotyping tasks. This automation can scale up the phenotyping measurements and evaluations that have to be performed to a larger number of plant samples and at a finer spatial and temporal resolution. In this paper, we investigate the problem of registering 3D point clouds of the plants over time and space. This means that we determine correspondences between point clouds of plants taken at different points in time and register them using a new, non-rigid registration approach. This approach has the potential to form the backbone for phenotyping applications aimed at tracking the traits of plants over time. The registration task involves finding data associations between measurements taken at different times while the plants grow and change their appearance, allowing 3D models taken at different points in time to be compared with each other. Registering plants over time is challenging due to its anisotropic growth, changing topology, and non-rigid motion in between the time of the measurements. Thus, we propose a novel approach that first extracts a compact representation of the plant in the form of a skeleton that encodes both topology and semantic information, and then use this skeletal structure to determine correspondences over time and drive the registration process. Through this approach, we can tackle the data association problem for the time-series point cloud data of plants effectively. We tested our approach on different datasets acquired over time and successfully registered the 3D plant point clouds recorded with a laser scanner. We demonstrate that our method allows for developing systems for automated temporal plant-trait analysis by tracking plant traits at an organ level. [ABSTRACT FROM AUTHOR]

Keywords: chlorophyll fluorescence; coordination; development; function; photosynthesis; plant water-use-efficiency; stomata EN chlorophyll fluorescence coordination development function photosynthesis plant water-use-efficiency stomata 350 352 3 03/22/22 20220415 NES 220415 What inspired your interest in plant science? I have a number of favourite plants, the top spot being shared between I Gingko i and I Dicksonia i tree ferns, possibly for similar reasons, i.e. the fact that they are "ancient plants", having first evolved many millions of years ago, and therefore provide us with a glimpse of the past. Chlorophyll fluorescence, coordination, development, function, photosynthesis, plant water-use-efficiency, stomata. [Extracted from the article]

This paper explores the links between genotype, plant development, plant structure and plant material properties. The barley husk has two organs, the lemma and the palea, which protect the grain. When the husk is exposed to mechanical stress, such as during harvesting, it can be damaged or detached. This is known as grain skinning , which is detrimental to grain quality and has a significant economic impact on industry. This study focused on the lemma, the husk organ which is most susceptible to grain skinning. This study tested three hypotheses: (1) genotype and plant development determine lemma structure, (2) lemma structure influences the material properties of the lemma, and (3) the material properties of the lemma determine grain skinning risk. The effect of genotype was investigated by using plant material from four malting barley varieties: two with a high risk of grain skinning, two with a low risk. Plant material was assessed at two stages of plant development (anthesis, GS 65; grain filling, GS 77). Structure was assessed using light microscopy to measure three physiological features: thickness, vasculature and cell area. Material properties were approximated using a controlled impact assay and by analyzing fragmentation behavior. Genotype had a significant effect on lemma structure and material properties from anthesis. This indicates that differences between genotypes were established during floral development. The lemma was significantly thinner in high risk genotypes, compared to low risk genotypes. Consequently, in high risk genotypes, the lemma was significantly more likely to fragment. This indicates a relationship between reduced lemma thickness and increased fragmentation. Traditionally, a thin husk has been considered beneficial for malting quality, due to an association with malt extract. However, this study finds a thin lemma is less resistant to mechanical stress. This may explain the differences in grain skinning risk in the genotypes studied. [ABSTRACT FROM AUTHOR]

Dr Klára Verseghy (1930-2020), a student of the famous Hungarian lichenologist Ödön Szatala, was working as the curator of the lichen collection of the Hungarian Natural History Museum, Budapest between 1958 and 1985. She did a great development in the lichen herbarium arranging and registering the big collections of F. Fóriss, V. Gyelnik and Ö. Szatala in the Zahlbruckner's system. Separating the type specimens she prepared also the type catalogue of the lichen collection in 1964. Approximately 5,000 lichen specimens were collected by herself in several areas of Hungary (e.g. Bakony Mts, Hortobágy, Kiskunság, Praenoricum, Vendvidék, Villány Mts, Zemp lén Mts) and ca 1,500 specimens from other countries (e.g. Finland, Norway, Poland, Romania, Slovakia, Sweden, Turkey and Ukraine). She published more than a hundred scientific and popular papers mainly on floristics, taxonomy, plant physiology and bioindication. Altogether 46 new taxa (19 species, 27 varieties and forms) and 69 new combinations were described by her. Following her taxonomic revisions (Caloplaca, Gasparrinia, Ochrolechia, Squamaria, Squamarina spp.) and floristical studies she prepared her main work "Magyarország zuzmóflórájának kézikönyve (The handbook of the Hungarian lichen flora)" in 1994. Her publications (106, including 23 in popular subject), her revisions and thousands of lichen specimens, the genus Verseghya and two species, Verseghya klarae and Verseghya thysanophora named after her preserve her memories. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Agricultura Irrigada - RBAI is the property of Revista Brasileira de Agricultura Irrigada - RBAI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Salinity is one of the major threats to sustainable agriculture that globally decreases plant production by impairing various physiological, biochemical, and molecular function. In particular, salinity hampers germination, growth, photosynthesis, transpiration, and stomatal conductance. Salinity decreases leaf water potential and turgor pressure and generates osmotic stress. Salinity enhances reactive oxygen species (ROS) content in the plant cell as a result of ion toxicity and disturbs ion homeostasis. Thus, it imbalances nutrient uptake, disintegrates membrane, and various ultrastructure. Consequently, salinity leads to osmotic and ionic stress. Plants respond to salinity by modulating various morpho-physiological, anatomical, and biochemical traits by regulating ion homeostasis and compartmentalization, antioxidant machinery, and biosynthesis of osmoprotectants and phytohormones, i. e, auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberellins, salicylic acid, jasmonic acid, and polyamines. Thus, this further modulates plant osmoticum, decreases ion toxicity, and scavenges ROS. Plants upregulate various genes and proteins that participate in salinity tolerance. They also promote the production of various phytohormones and metabolites that mitigate the toxic effect of salinity. Based on recent papers, the deleterious effect of salinity on plant physiology is discussed. Furthermore, it evaluates the physiological and biochemical responses of the plant to salinity along with phytohormone response. This review paper also highlights omics (genomics, transcriptomics, proteomics, and metabolomics) approach to understand salt stress tolerance. • Salt stress creates ionic and osmotic stress on plants. • Salinity harms morphological and biochemical functions in plants. • Plants respond to salinity by various strategies involve the complex physiological traits, and metabolic pathways. [ABSTRACT FROM AUTHOR]

Plant breeders are in the need for a convenient, reproducible, reliable and rapid screening methods to be used as a proxy for drought tolerance for a large number of genotypes. Addressing this need, we compared different physiological measures of stress in six barley (Hordeum vulgare L.) genotypes subjected to different drought treatments under glasshouse conditions. Genotypes were evaluated by measuring transpiration rate, quantum yield of PSII (chlorophyll fluorescence Fv/Fm ratio), SPAD chlorophyll meter reading, dry biomass and shoot water content. The accuracy of different methods for quantifying water stress tolerance was evaluated by measuring the rates of surviving and death in plants and leaves, and newly grown leaves after rewatering. In another experiment, the same genotypes were evaluated by applying 18% (w/v) of polyethylene glycol (PEG) to germinating seeds grown in paper rolls to induce osmotic stress, using relative root and shoot lengths as a measure of tolerance. The results suggest that transpiration measurements at the recovery stage could be the most sensitive method for separating contrasting genotypes. However, the method is time-consuming and laborious for large-scale screening. Chlorophyll content, dry biomass, shoot water content and stomatal density did not correlate with plant drought tolerance. At the same time, chlorophyll fluorescence Fv/Fm ratio showed a strong correlation with drought tolerance and could be recommended as suitable proxy for screening. Measuring relative root growth rate (length) using PEG-treated paper roll-grown seedlings also seems to be a highly suitable and promising method for screening a large number of genotypes in breeding programs. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Agronomy is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper characterizes pre-germination behavior and catecholase (PPO) activity in mature seeds, seed testa and several laboratory separated seed testa strata of Phaseolus lunatus. Imbibition coefficients were 1.56 for whole seeds, 3.14 for whole testa, 2.6 for exotesta, 3.25 for meso and endotesta, 3.9 for mesotesta and 2.54 for endotesta. Enzymatic activity was measured polarographically. Catecholase activity was clearly deatectable and measured in all samples. The lowest activity was in whole seed with the total testa (11.0 nmol O2 h-1 gdm-1) and highest in the separated total testa (743.0 nmol O2 h-1 gdm-1). Separation of the testa strata showed differences in catecholase activity in the different strata (397.3 nmol O2 h-1 gdm-1 in exotesta, 155.5 nmol O2 h-1 gdm-1 in meso and endotesta combined, but 119.7 nmol O2 h-1 gdm-1 in the separated mesotesta and only 35.0 nmol O2 h-1 gdm-1 in the separated endotesta). The novel contribution of the present paper is the analysis of the relative contribution of different testa subfractions to the pool of catecholase activity, indicating that catecholase activity in whole seed is lower than in testa. The variations in catecholase activity were relatively large. The results demonstrate the functional role of catecholase and can be used in plant breeding and plant biotechnologies to promote immunity and germination. [ABSTRACT FROM AUTHOR]

Over the past few decades seed physiology research has contributed to many important scientific discoveries and has provided valuable tools for the production of high quality seeds. An important instrument for this type of research is the accurate quantification of germination; however gathering cumulative germination data is a very laborious task that is often prohibitive to the execution of large experiments. In this paper we present thegerminator package: a simple, highly cost-efficient and flexible procedure for high-throughput automatic scoring and evaluation of germination that can be implemented without the use of complex robotics. Thegerminator package contains three modules: (i) design of experimental setup with various options to replicate and randomize samples; (ii) automatic scoring of germination based on the color contrast between the protruding radicle and seed coat on a single image; and (iii) curve fitting of cumulative germination data and the extraction, recap and visualization of the various germination parameters. The curve-fitting module enables analysis of general cumulative germination data and can be used for all plant species. We show that the automatic scoring system works for Arabidopsis thaliana and Brassica spp. seeds, but is likely to be applicable to other species, as well. In this paper we show the accuracy, reproducibility and flexibility of thegerminator package. We have successfully applied it to evaluate natural variation for salt tolerance in a large population of recombinant inbred lines and were able to identify several quantitative trait loci for salt tolerance.germinator is a low-cost package that allows the monitoring of several thousands of germination tests, several times a day by a single person. [ABSTRACT FROM AUTHOR]

Copyright of Agricultural Research in the Tropics / Pesquisa Agropecuária Tropical is the property of Pesquisa Agropecuaria Tropical and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Physiological and management modifications to increase crop yields require an appreciation of the impact of these changes on a geospatial basis. It is quite possible that the yield response to any modification may vary from positive in one location to negative in another location. Therefore, tools to undertake geospatial analysis are required to assess the overall impact. It is argued that mechanistic models based on the physics and physiology of plant development, growth, and yield formation are required for such tasks. Several criteria in selecting model tools are discussed. First, models that need to be "calibrated" are not suited for geospatial assessments because the calibration processes causes the model to be an empirical representation of the calibration data and limited to the calibration environment. Extreme caution is needed to extrapolate model use beyond the domain of calibration, since geospatial analysis requires the model to be run for a range of geographical locations over a number of growing seasons. Second, to readily understand the output from simulations across space and time, models needs to be compact and transparent so output that seems inconsistent or not intuitively obvious can be tracked to the critical features in the model. Models with a smaller number of parameters are likely to be more transparent. Finally, it is necessary that the robustness of the model has been tested against a range of environmental conditions. In this paper, we discuss the example of the Simple Simulation Model (SSM) as an option that meets these criteria. [ABSTRACT FROM AUTHOR]

Methane (CH4), one of the most important greenhouse gases, has conventionally been considered as a physiologic inert gas. However, this perspective has been challenged by the observation that CH4 has diverse biological functions in animals, such as anti-inflammatory, antioxidant, and anti-apoptosis. Meanwhile, it has now been identified as a possible candidate of gaseous signaling molecule in plants, although its biosynthetic and metabolic pathways as well as the mechanism(s) of CH4 signaling have not fully understood yet. This paper aims to review the available evidence for the biological roles of CH4 in regulating plant physiology. Although currently available reports do not fully support the notion of CH4 as a gasotransmitter, they do show that CH4 might be produced by an aerobic, non-microbial pathway from plants, and plays important roles in enhancing plant tolerance against abiotic stresses, such as salinity, drought, heavy metal exposure, and promoting root development, as well as delaying senescence and browning. Further results showed that CH4 could interact with reactive oxygen species (ROS), other gaseous signaling molecules [e.g., nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S)], and glutathione (GSH). These reports thus support the idea that plant-produced CH4 might be a component of a survival strategy of plants. Finally, the possibility of CH4 application in agriculture is preliminarily discussed. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Laboratory experiments were conducted to determine the allelopathic potential of 17 Iranian barley cultivars in four development stages and their variations over the last 60 years of collection. Imbibed seeds and water leachates that were extracted from the barley plants at the seedling, tillering, stem elongation, and heading stages were used for the bioassays, including filter paper, neighboring barley seeds in soil, and soil mixed with dried barley residues. The experiments were conducted with the use of wild mustard ( Sinapis arvensis) as the test plant. The Germination Rate Index (GRI) and emergence of S. arvensis were inhibited on both the filter paper and soil. The highest inhibitory effect was seen with the tillering stage's water leachate on filter paper. The GRI decreased in response to the increased density of barley imbibed seeds. The germination was less affected by the presence of barley seeds from the soil than those from the filter paper. The GRI of S. arvensis seeds was lower in the older than in the recently developed cultivars. Although there were some fluctuations in the GRI value with time, the germination inhibitory effect has decreased as new, higher-yielding cultivars have been released. [ABSTRACT FROM AUTHOR]

Abstract: Previous QTL studies on seedling vigor in rice (Oryza sativa L.) were conducted all based on laboratory germination tests. In the current study, a set of recombinant inbred lines derived from a rice cross were assessed for seedling vigor related traits in natural field environments including two treatments (drained soil and flooded soil). Composite interval mapping identified nine QTL for seedling vigor traits that correlated positively with each other. Individual QTL explained 4–14% of the total trait variation. Among the QTL, three and four were specific to the drained and flooded treatments, respectively, while two others were common between the two treatments. Four QTL (qFV-1-1, qFV-3-2, qFV-5-1 and qFV-10) each simultaneously showed effect on two or more traits with additive effects always in the same direction. The QTL qFV-5-1 could be further resolved into at least two linked loci, qFV-5-1a controlling seedling height and qFV-5-1b controlling seedling dry weight while the QTL qFV-10 could be a single locus with a pleiotropic effect on both seedling height and dry weight. The QTL qFV-1-1 and qFV-3-2 expressed specially under the flooded conditions, each pleiotropically controlling both coleoptile and seedling emergence. These two QTL were completely different from that affecting seedling emergence in the drained conditions. Comparison of the QTL indicated that the QTL mapping results based on field assessments could to some extent coincide with those based on lab tests but the discrepancy between the two kinds of experiments could not be overlooked. [Copyright &y& Elsevier]

As a prelude to direct sowing experiments, a laboratory study was carried out to determine whether six chemicals with insect and/or rodent repellent properties (Aaprotect, Capsaicin, Guardsman, Hallmark, Scuttle, Treeguard) affected the germination capacities and/or viability percentages of European ash (Fraxinus excelsior L.), silver birch (Betula pendula L.), Corsican pine (Pinus nigra ssp. laricio L.) and sycamore (Acer pseudoplatanus L.) seeds. None of the chemical repellents had a significant effect on either the germination capacity or viability of ash or birch seeds. One repellent (Guardsman) significantly reduced the germination capacity of sycamore from 49 to 32 per cent (P 0.01). Two repellents (Aaprotect and Scuttle) significantly reduced the germination capacity of Corsican pine from 74 to 62 per cent (P 0.05) and 11 per cent (P 0.001), respectively. Corsican pine was therefore the most sensitive of the species investigated to phytotoxic effects. Viability percentages (at the end of germination tests on repellent-treated seeds) showed that virtually all ungerminated seeds were dead. Greater phytotoxicity was observed for small-seeded species when they were incubated on a substrate of moist filter paper than when they were sown in moist peat + sand. One explanation is that the larger volume of peat + sand in the seed-tray allowed the chemicals to leach away from the seeds more quickly. Alternatively, perhaps the peat inactivated the chemicals through adsorption. The results are used to exclude certain chemical and tree seed combinations from future seed predation studies associated with direct sowing. [ABSTRACT FROM AUTHOR]

Recent research has demonstrated that characteristic gene selection based on gene expression data remains faced with considerable challenges. This is primarily because gene expression data are typically high dimensional, negative, non-sparse and noisy. However, existing methods for data analysis are able to cope with only some of these challenges. In this paper, we address all of these challenges with a unified method: nonnegative matrix factorization via the L2,1-norm (NMF-L2,1). While L2,1-norm minimization is applied to both the error function and the regularization term, our method is robust to outliers and noise in the data and generates sparse results. The application of our method to plant and tumor gene expression data demonstrates that NMF-L2,1 can extract more characteristic genes than other existing state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Brassinosteroids are endogenous plant hormones essential for the normal regulation of multiple physiological processes including cell elongation and division, vascular differentiation, vegetative and reproductive development, and numerous responses to the environment. Since the discovery of the chemical structure of brassinolide more than 35 years ago, extensive research on the mechanisms of BR action has helped define the BR biosynthetic pathway and identify the basic molecular components of BR signal transduction. This article provides historical context of studies from 1970 through 2005 involving chemistry, molecular genetics, and physiology that have provided the foundation for further mechanistic advances describing pathways and regulatory networks through which BR influences many aspects of plant growth and development. [ABSTRACT FROM AUTHOR]

Introduction: Breeding programs have developed high-yielding Coffea arabica F1-hybrids as an adaptation against adverse conditions associated with climate change. However, theresponse to drought of coffee F1 hybrids has seldom been assessed. Methods: A trial was established with five C. arabica genotypes (2 pure lines: Catimor and Marsellesa and 3 F1 hybrids: Starmaya, Centroamericano and Mundo Maya) planted under the leguminous tree species Leuceana leucocephala. Coffee growth, yield and physiological responses were assessed under a rain-fed (control: CON) and a rainfall reduction treatment (RR) for 2 years. Results: The RR treatment created a long-term rainfall deficit in a region with suboptimal temperature similar to those predicted by climate change scenarios. Moreover, the RR treatment reduced soil water content by 14% over 2 successive years of production and increased hydric stress of the three F1-hybrids (leaf water potentials averaged -0.8 MPa under RR compared with -0.4 MPa under CON). Under RR, coffee yields were reduced from 16 to 75% compared to CON. Mundo Maya F1 hybrid was the sole high-yielding genotype apable of sustaining its yield under RR conditions. Our results suggested that its significant increase in fine root density (CON = 300 and RR = 910 root.m-2) and its maintenance of photosynthetic rate (2.5 - 3.5 mmol CO2 m-2 s-1) at high evaporative demand might explain why this genotype maintained high yield under RR condition. Discussion: This work highlights a possible drought tolerance mechanism in fruit bearing adult coffee trees where the plant fine root number increases to intake more water in order to preserve turgor and sustainphotosynthesis at high ETo and therefore conserves high yield in dry conditions. [ABSTRACT FROM AUTHOR]

Background: As identified by the research, it is imperative to develop effective ways to address the pressing problem of disease and pest susceptibility in chili agriculture and secure sustainable crop yield. The research examines the impact of various growing microclimates, watering regimens, and chili cultivars on disease incidence, pest attacks, and yield loss. Results: The study, which took place over a season, used a randomized complete block design to evaluate how well Tanjung, Unpad, and Osaka cultivars performed in four different watering regimens (100, 75, 50, and 25% ETc) and different microclimates (greenhouse, rain shelter, screen house, and open field). The findings exhibited that watering regimens and microclimates greatly influenced disease and pest occurrence, but cultivars had a minimal effect on these variables. Disease and pest attack rates were highest in the open field and lowest in the screen house. A correlation was found between lower disease and pest incidence and optimal irrigation levels (75% and 100% ETc). At lower watering regimens of 25% ETc and in the open field, yield loss was the greatest. Conclusion: The results emphasize how crucial controlled environments and appropriate irrigation techniques are to reducing crop loss and increasing production. Enhancing watering regimens and implementing screen house cultivation are two strategies for improving the productivity and sustainability of chili output. [ABSTRACT FROM AUTHOR]

The stress that the space environment can induce on plant physiology is of both abiotic and biotic nature. The abiotic space environment is characterized by ionizing radiation and altered gravity, geomagnetic field (GMF), pressure, and light conditions. Biotic interactions include both pathogenic and beneficial interactions. Here, we provide an overall picture of the effects of abiotic and biotic space-related factors on plant physiology. The knowledge required for the success of future space missions will lead to a better understanding of fundamental aspects of plant physiological responses, thus providing useful tools for plant breeding and agricultural practices on Earth. A review summarizes the effects of abiotic (ionizing radiation, altered gravity, geomagnetic field, pressure, and light conditions) and both beneficial and pathogenic biotic space-related factors on plant physiology. [ABSTRACT FROM AUTHOR]

This study explored the drought resistance mechanisms of different populations of Sporobolus ioclados (Poaceae), locally known as "Sawri," "Drabhri" and "Dhrbholi" native to Africa and the Indian Subcontinent. These populations were grown in conventional nursery practices at Khawaja Fareed Government College in Rahim Yar Khan, Pakistan, and subsequently subjected to four distinct levels of drought within carefully monitored experimental settings. The experiment was conducted in a two-factorial design involving populations and drought treatments and was repeated three times. The physiological and morphological responses of S. ioclados, including plant height, number of roots, root length, flag leaf area, stomatal features, proline concentration and nitrogen content, displayed significant variability in response to the imposed drought stress. Drought resulted in increases in proline concentration and nitrogen content. The number of roots decreased, while the length and width of the stomata increased in various populations. A combination of advanced statistical techniques, such as ANOVA, PCA, HCA, and DFA, provided a comprehensive understanding of the mechanism of plant adaptation and the extent of population diversity within the species. The Yazman and Nwab Wala populations exhibited the highest rates of photosynthesis and stomatal conductance, while S. ioclados demonstrated notable drought tolerance at the T4 level of drought stress. A negative correlation was found between proline levels, nitrogen contents, and photosynthesis, suggesting that proline has a protective role in drought. The diverse adaptation strategies indicated by S. ioclados populations have revealed the potential of this species for afforestation and climate change mitigation in dry environments. [ABSTRACT FROM AUTHOR]