Do Hydro-Retainer Polymers Attenuate Damage from Water Fluctuations in Leaf Metabolism and the Quality of Cedrela odorata Seedlings?

Water stress, caused by excess or lower of water, can negatively affect leaf metabolism and seedling growth and prevent it from developing its maximum genetic potential. In this sense, it is necessary to use as that can mitigate these deleterious effects on plants at their initial phase of growth. The aim of this work was to evaluate the effect of hydrogel in the mitigation of water stress (deficit and flooding) on photosynthetic metabolism and growth characteristics of C. odorata seedlings, and also evaluate their recovery potential after the resumption of irrigation. The characteristics of photosynthetic metabolism, growth and quality of C. odorata seedlings showed a reduction caused by water fluctuations, indicating sensitivity to these conditions, although photosynthesis photochemistry was affected to a lower extent. The addition of the hydro-retainer polymer contributed little to the biochemical and photochemical indicators of photosynthesis and seedling quality, a fact that directs us to reject our hypothesis that its use promotes mitigation of damage to the photosynthetic apparatus and to the growth. Cedrela odorata is sensitive to water variations in the soil, but recovers the photosynthetic metabolism and quality of the seedlings once the stressful water condition is suspended. The application of the hydro-retainer polymer mitigated, but the seedlings recovered regardless of their presence. © 2021 Friends Science Publishers

Environment-coupled models of leaf metabolism

The plant leaf is the main site of photosynthesis. This process converts light energy and inorganic nutrients into chemical energy and organic building blocks for the biosynthesis and maintenance of cellular components and to support the growth of the rest of the plant. The leaf is also the site of gas–water exchange and due to its large surface, it is particularly vulnerable to pathogen attacks. Therefore, the leaf's performance and metabolic modes are inherently determined by its interaction with the environment. Mathematical models of plant metabolism have been successfully applied to study various aspects of photosynthesis, carbon and nitrogen assimilation and metabolism, aided suggesting metabolic intervention strategies for optimized leaf performance, and gave us insights into evolutionary drivers of plant metabolism in various environments. With the increasing pressure to improve agricultural performance in current and future climates, these models have become important tools to improve our understanding of plant–environment interactions and to propel plant breeders efforts. This overview article reviews applications of large-scale metabolic models of leaf metabolism to study plant–environment interactions by means of flux-balance analysis. The presented studies are organized in two ways — by the way the environment interactions are modelled — via external constraints or data-integration and by the studied environmental interactions — abiotic or biotic.

Changes on Potato Leaf Metabolism and Anatomy Induced by Plant Growth Regulators

The use of growth regulators in potato crop is an alternative to reduce the aerial growth of plants and redirects carbon assimilates and nutrients to the tubers. Therefore, the objective of this study was to evaluate the effects of growth regulators, paclobutrazol and trinexapac-ethyl on plant growth and changes on the anatomy of leaves of cultivar Markies in summer conditions of the southern region of Brazil. Potato plants cv. Markies were in the summer growing season of Southeast region of Brazil and 35 days after planting, the plants were sprayed with paclobutrazol (PBZ) at 0.125 and 0.250 L ha-1 and trinexapac-ethyl (TE) at 1.0 and 2.0 L ha-1. Treatment with PBZ at both doses reduced the height of potato plants, which resulted in higher index of leaf chlorophyll and reduced the content of starch and non-reducing sugars. Both PBZ and TE treated plants exhibited anatomical changes in the leaves, including larger epidermal cells and more elongated palisades cells. These data suggest that such changes in the anatomy of potato leaf in response to the use of PBZ directly influence leaf metabolism.