Contents

**Preface XI**


Weronika Wituszyńska and Stanisław Karpiński

#### **X** Contents

#### **Section 2 Applications in Agriculture 247**


## Preface

**Section 2 Applications in Agriculture 247**

**VI** Contents

**Wild Apples 249** Carole L. Bassett

Pavel Pavloušek

**Grapevine Rootstocks 277**

Kourosh Vahdati and Naser Lotfi

**Abiotic Stresses 367**

Allan T. Showler

Chapter 8 **Water Use and Drought Response in Cultivated and**

Chapter 9 **Tolerance to Lime - Induced Chlorosis and Drought in**

Chapter 10 **Abiotic Stress Tolerance in Plants with Emphasizing on Drought and Salinity Stresses in Walnut 307**

Chapter 11 **The Role of Transcription Factors in Wheat Under Different**

Mahdi Rahaie, Gang-Ping Xue and Peer M. Schenk

Chapter 12 **Water Deficit Stress - Host Plant Nutrient Accumulations and Associations with Phytophagous Arthropods 387**

Abiotic stresses are serious threats to agriculture and the environment which have been exa‐ cerbated in the current century by global warming and industrialization. According to FAO statistics, more than 800 million hectares of land throughout the world are currently salt-af‐ fected, including both saline and sodic soils equating to more than 6% of the world's total land area. Continuing salinization of arable land is expected to have overwhelming global impact, resulting in a 30% loss of agricultural land over the next 25 years and up to 50% loss by 2050. Overall, it has been estimated that the world is losing at least 3 ha of arable land every minute due to soil salinity. Some of the most serious effects of abiotic stresses occur in the arid and semiarid regions where low rainfall, high evaporation, native rocks, saline irri‐ gation water, and poor water management all contribute in agricultural areas.

As stated in one of the chapters of this book, Kofi Annan has proposed a "Blue Revolution in Agriculture" as we enter the current millennium, an international initiative focusing on increasing our productivity per unit of water in order to achieve "More crop per drop". Ef‐ forts to improve the efficiency of agricultural water use while simultaneously reducing ad‐ verse environmental impacts will need to draw on results of extensive and diverse research in several areas. Over the last few decades there has been tremendous progress in under‐ standing the molecular, biochemical, and physiological basis of stress tolerance in plants. As we move forward, emerging information and novel approaches must continuously be ap‐ plied in a timely and effective manner by both the research and applied agricultural com‐ munities. One promising approach to improving the ability of plants to cope with abiotic stress is to combine utilization of the vast biodiversity of crop plants and their wild relatives with the rapidly emerging genetic and molecular techniques. Global programs, such as the Global Partnership Initiative for Plant Breeding Capacity Building (GIPB), aim to select and distribute seed crops and cultivars with tolerance to abiotic stresses in order to facilitate sus‐ tainable use of plant genetic resources for food and agriculture.

Abiotic stress leads to a series of morphological, physiological, biochemical and molecular changes in plants that adversely affect growth and productivity. A frequent result is protein dysfunction. Understanding the mechanisms of protein folding stability and how this knowledge can be utilized is one of the most challenging strategies for aiding organisms undergoing stress conditions. Stresses also affect the biosynthesis, concentration, transport, and storage of primary and secondary metabolites. As a more comprehensive view of these processes evolves, applications to reducing plant stress are emerging.

While much has been achieved in recent years in developing plants genetically engineered for resistance to herbicides, pests and diseases, production of plants engineered for tolerance to abiotic stress has not progressed as rapidly and applications in canola, rice and maize, for

example, have only recently begun to be commercialized. This is due largely to the more complex genetic mechanisms involved in tolerance to abiotic stresses. Additionally, under natural conditions plants can suffer from various stress combinations at different develop‐ ment stages and during different time periods. Many of the gene products differentially ex‐ pressed under stress, such as dehydrins, enzymes for the synthesis of osmolytes, and enzymes for the removal of reactive oxygen species (ROS), protect plant cells from damage. The production of these functional proteins is widely regulated by specific transcription fac‐ tors. Use of transcription factors is now under development as an additional biotechnologi‐ cal approach to improving plant response to abiotic stresses.

This book is not intended to cover all known abiotic stresses or every possible technique used to understand plant tolerance but instead to describe some of the widely used ap‐ proaches to addressing such major abiotic stresses as drought, salinity, extreme tempera‐ ture, cold, light, calcareous soils, excessive irradiation, ozone, ultraviolet radiation, and flooding, and to describe major or newly emerging techniques employed in understanding and improving plant tolerance. Among the strategies for plant stress survival, deep rooting, programmed cell death and accumulation of compatible osmolytes are presented in detail and comprehensive case studies of progress and directions in several agricultural crops such as apple, walnut, grape and wheat are included.

> **Kourosh Vahdati** University of Tehran, Iran

**Charles Leslie** University of California-Davis, USA **Mechanisms of Response and Adaptation**

example, have only recently begun to be commercialized. This is due largely to the more complex genetic mechanisms involved in tolerance to abiotic stresses. Additionally, under natural conditions plants can suffer from various stress combinations at different develop‐ ment stages and during different time periods. Many of the gene products differentially ex‐ pressed under stress, such as dehydrins, enzymes for the synthesis of osmolytes, and enzymes for the removal of reactive oxygen species (ROS), protect plant cells from damage. The production of these functional proteins is widely regulated by specific transcription fac‐ tors. Use of transcription factors is now under development as an additional biotechnologi‐

This book is not intended to cover all known abiotic stresses or every possible technique used to understand plant tolerance but instead to describe some of the widely used ap‐ proaches to addressing such major abiotic stresses as drought, salinity, extreme tempera‐ ture, cold, light, calcareous soils, excessive irradiation, ozone, ultraviolet radiation, and flooding, and to describe major or newly emerging techniques employed in understanding and improving plant tolerance. Among the strategies for plant stress survival, deep rooting, programmed cell death and accumulation of compatible osmolytes are presented in detail and comprehensive case studies of progress and directions in several agricultural crops such

**Kourosh Vahdati**

**Charles Leslie**

University of Tehran, Iran

University of California-Davis, USA

cal approach to improving plant response to abiotic stresses.

as apple, walnut, grape and wheat are included.

VIII Preface
