Plant Biology 

About: Plant Biology is an academic journal published by Wiley. The journal publishes majorly in the area(s): Population & Pollination. It has an ISSN identifier of 1435-8603. Over the lifetime, 3164 publications have been published receiving 106897 citations. The journal is also known as: Plant biology (Stuttgart. Print).

Transcriptional regulatory networks in cellular responses and tolerance to dehydration and cold stresses.

Abstract: Plant growth and productivity are greatly affected by environmental stresses such as drought, high salinity, and low temperature. Expression of a variety of genes is induced by these stresses in various plants. The products of these genes function not only in stress tolerance but also in stress response. In the signal transduction network from perception of stress signals to stress-responsive gene expression, various transcription factors and cis-acting elements in the stress-responsive promoters function for plant adaptation to environmental stresses. Recent progress has been made in analyzing the complex cascades of gene expression in drought and cold stress responses, especially in identifying specificity and cross talk in stress signaling. In this review article, we highlight transcriptional regulation of gene expression in response to drought and cold stresses, with particular emphasis on the role of transcription factors and cis-acting elements in stress-inducible promoters.

The lipoxygenase pathway.

Abstract: Lipid peroxidation is common to all biological systems, both appearing in developmentally and environmentally regulated processes of plants. The hydroperoxy polyunsaturated fatty acids, synthesized by the action of various highly specialized forms of lipoxygenases, are substrates of at least seven different enzyme families. Signaling compounds such as jasmonates, antimicrobial and antifungal compounds such as leaf aldehydes or divinyl ethers, and a plant-specific blend of volatiles including leaf alcohols are among the numerous products. Cloning of many lipoxygenases and other key enzymes within the lipoxygenase pathway, as well as analyses by reverse genetic and metabolic profiling, revealed new reactions and the first hints of enzyme mechanisms, multiple functions, and regulation. These aspects are reviewed with respect to activation of this pathway as an initial step in the interaction of plants with pathogens, insects, or abiotic stress and at distinct stages of development.

Diffusive and metabolic limitations to photosynthesis under drought and salinity in C(3) plants.

Abstract: Drought and salinity are two widespread environmental conditions leading to low water availability for plants. Low water availability is considered the main environmental factor limiting photosynthesis and, consequently, plant growth and yield worldwide. There has been a long-standing controversy as to whether drought and salt stresses mainly limit photosynthesis through diffusive resistances or by metabolic impairment. Reviewing in vitro and in vivo measurements, it is concluded that salt and drought stress predominantly affect diffusion of CO(2) in the leaves through a decrease of stomatal and mesophyll conductances, but not the biochemical capacity to assimilate CO(2), at mild to rather severe stress levels. The general failure of metabolism observed at more severe stress suggests the occurrence of secondary oxidative stresses, particularly under high-light conditions. Estimates of photosynthetic limitations based on the photosynthetic response to intercellular CO(2) may lead to artefactual conclusions, even if patchy stomatal closure and the relative increase of cuticular conductance are taken into account, as decreasing mesophyll conductance can cause the CO(2) concentration in chloroplasts of stressed leaves to be considerably lower than the intercellular CO(2) concentration. Measurements based on the photosynthetic response to chloroplast CO(2) often confirm that the photosynthetic capacity is preserved but photosynthesis is limited by diffusive resistances in drought and salt-stressed leaves.

Boron in Plant Biology

Abstract: The interest of biologists in boron (B) has largely been focused on its role in plants for which B was established as essential in 1923 (Warington, 1923[296]). Evidence that B has a biological role in other organisms was first indicated by the establishment of essentiality of B for diatoms (Smyth and Dugger, 1981[296]) and cyanobacteria (Bonilla et al., 1990[296]; Garcia-Gonzalez et al., 1991[296]; Bonilla et al., 1997[296]). Recently, B was shown to stimulate growth in yeast (Bennett et al., 1999[296]) and to be essential for zebrafish (Danio rerio) (Eckhert and Rowe, 1999[296]; Rowe and Eckhert, 1999[296]) and possibly for trout (Oncorhynchus mykiss) (Eckhert, 1998[296]; Rowe et al., 1998[296]), frogs (Xenopus laevis) (Fort et al., 1998[296]) and mouse (Lanoue et al., 2000[296]). There is also preliminary evidence to suggest that B has at least a beneficial role in humans (Nielsen, 2000[296]). While research into the role of B in plants has been ongoing for 80 years it has only been in the past 5 years that the first function of B in plants has been defined. Boron is now known to be essential for cell wall structure and function, likely through its role as a stabilizer of the cell wall pectic network and subsequent regulation of cell wall pore size. A role for B in plant cell walls, however, is inadequate to explain all of the effects of B deficiency seen in plants. The suggestion that B plays a broader role in biology is supported by the discovery that B is essential for animals where a cellulose-rich cell wall is not present. Careful consideration of the physical and chemical properties of B in biological systems, and of the experimental data from both plants and animals suggests that B plays a critical role in membrane structure and hence function. Verification of B association with membranes would represent an important advance in modern biology. For several decades there has been uncertainty as to the mechanisms of B uptake and transport within plants. This uncertainty has been driven by a lack of adequate methodology to measure membrane fluxes of B at physiologically relevant concentrations. Recent experimentation provides the first direct measurement of membrane permeability of B and illustrates that passive B permeation contributes sufficient B at adequate levels of B supply, but would be inadequate at conditions of marginal B supply. The hypothesis that an active, carrier mediated process is involved in B uptake at low B supply is supported by research demonstrating that B uptake can be stimulated by B deprivation, that uptake rates follow a Michaelis-Menton kinetics, and can be inhibited by application of metabolic inhibitors. Since the mechanisms of element uptake are generally conserved between species, an understanding of the processes of B uptake is relevant to studies in both plants and animals. The study of B in plant biology has progressed markedly in the last decade and we are clearly on the cusp of additional, significant discoveries. Research in this field will be greatly stimulated by the discovery that B is essential for animals, a discovery that will not only encourage the participation of a wider cadre of scientists but will refocus the efforts of plant biologists toward a determination of roles for B outside the plant cell wall. Determination of the function of B in biology and of the mechanisms of B uptake in biological systems, is essential to our understanding and management of B deficiency and toxicity in plants and animals in both agricultural and natural environments. Through an analysis of existing data and the development of new hypotheses, this review aims to provide a vision of the future of research into the biology of boron.

Significance of flavonoids in plant resistance and enhancement of their biosynthesis.

Abstract: The roles of flavonoids in plant defence against pathogens, herbivores, and environmental stress are reviewed and their significant contribution to plant resistance is discussed. The induction of flavonoids is of particular interest for gathering evidence of their roles. Tools are mentioned which may enhance flavonoid biosynthesis and accumulation. These include metabolic engineering and UV light. The induction of defence-related flavonoids is modified by other determining factors and competition between growth and secondary metabolism may exist. In an evolutionary context, stress-related oxidative pressure may have been a major trigger for the distribution and abundance of flavonoids. UV protection is one of their most significant, or even the most significant, functional role for flavonoids. The multi-functionality of these compounds, however, often complicates the interpretation of experimental results but, overall, it supports the importance of flavonoids.