List of Contributors Preface 1. Introduction K.V. Madhava Rao.- 2.Water Stress A. Yokota, K. Takahara and K. Akashi.- 3.Salt Stress Zora Dajic .- 4. High Temperature Stress Thomas D. Sharkey and Stephen M. Schrader.- 5. Freezing Stress Russell G. Trischuk, Brian S. Schilling, M. Wisniewski and Lawrence V. Gusta .- 6.Photooxidative Stress Attipalli R. Reddy and Agepati S. Raghavendra.- 7.Nutrient Stress K. Janardhan Reddy.- 8.Heavy Metal Stress Ksenija Gasic and Schuyler S. Korban.- 9.Metabolic Engineering for Stress Tolerance Bala Rathinasabapathi and Ramandeep Kaur.- 10.Functional Genomics of Stress Tolerance Akhilesh K. Tyagi, Shubha Vij and Navinder Saini.- Index

Physiology and molecular biology of stress tolerance in plants

This article presents the theoretical motivation, implementation approach, and example validation results for a computationally efficient plume simulation model, designed to replicate both the short-term time signature and long-term exposure statistics of a chemical plume evolving in a turbulent flow. Within the resulting plume, the odor concentration is intermittent with rapidly changing spatial gradient. The model includes a wind field defined over the region of interest that is continuous, but which varies with location and time in both magnitude and direction. The plume shape takes a time varying sinuous form that is determined by the integrated effect of the wind field. Simulated and field data are compared. The motivation for the development of such a simulation model was the desire to evaluate various strategies for tracing odor plumes to their source, under identical conditions. The performance of such strategies depends in part on the instantaneous response of target receptors; therefore, the sequence of events is of considerable consequence and individual exemplar plume realizations are required. Due to the high number of required simulations, computational efficiency was critically important.

Filament-based atmospheric dispersion model to achieve short time-scale structure of odor plumes

Forest Decline and Air Pollution

Air Pollution by Photochemical Oxidants

Tropospheric ozone produced by industrial civilization is widespread. Although the levels are not clearly life threatening, they do have the potential to inhibit normal plant productivity, thought to be by an inhibition of photosynthesis. While the mechanism for this inhibition is not yet clear, there are several hypotheses for its cause. It is unlikely that ozone can penetrate the cell membrane unreacted; therefore, reactions at the plasma membrane either causing general ionic and metabolic disturbance within the cell or causing the production of unidentified toxic products must ultimately produce the alterations within the chloroplasts. While model systems, such as individual biochemicals, isolated chloroplasts, and algae, can give some understanding of possible reactions, they cannot provide the full story. One continuing controversy revolves about the role of stomata in the inhibition process-they play an important role, but the full interaction between stomatal closure and inhibition of photosynthesis has not yet emerged. In order to reach a political compromise on air quality standards, we need to have a good understanding of the fundamental mechanisms by which ozone causes any decline in plant productivity.

Possible mechanisms for the inhibition of photosynthesis by ozone

As shown in an early field study in the 1970s, ozone-sensitive varieties of potatoes (left rows) show reduced growth and lower yields than ozone-tolerant varieties (right rows). While its effects are often overlooked, air pollution negatively impacts crops around the world, resulting in significant economic losses, with the greatest economic loss occurring in the United States. Satellites can give farmers, scientists and policy makers important knowledge of how air quality affects food security, enabling more informed decision-making to ensure access to food resources.

Thomas

Papers

Effects of air pollution on plants.