Rishikesh Upadhyay

This book, in a comprehensive manner, provides an overview of the challenges of increasing crop or agricultural productivity to meet the demands of a growing population, linking descriptions of physiological, ecological, biochemical and molecular activity in plants with their tolerance and adaptation to natural environments. In the case of plants, a stress is an adverse condition or substance that affects or blocks a plant’s metabolism, growth, or development. The threat to productivity in crops and agriculture due to these stresses cannot be overstated, nor overlooked, especially in light of climate change. The information covered in this book will be helpful in building strategies to counter the impact of stress on plants. The book also provides an overview of the essential disciplines required for sustainable crop and agricultural production for policymakers, scientists, academics, and students of plant science, agricultural science, environmental science, biochemistry, biotechnology, and related areas.

Excess toxicity due to oxygen deficiency during natural submergence or flash flooding poses a potential hazard. Oxygen is essential of being alive for all the aerobic organisms. On the other hand, though the generation of reactive oxygen species (ROS) can affect both positive and negative roles, or that the ROS acts as an oxidative molecule, yet it does have enough potential to cause toxicity in plants, such as rice (Oryza sativa L.) treated as semi-aquatic plant and is adapted to survive submergence for a considerable period of time. Further, rice can withstand submergence stress either by its inherent metabolic adaptations or by keeping its leaves above the water surface by continuously elongating the stem. The present work intends to review the physiological and biochemical adaptations of rice plants on re-oxygenation or re-aeration after the submergence stress.

The deficiency of oxygen in water during submergence is one of the frequently perceived environmental factors that limits or hampers production of the rice cultivation. Rice plants comprise of elongated submerged tissues that help to bear with the rise of water level in natural location. This characteristic helps the plant to deal with flooding stress. The mechanism on flooding tolerance and adaptation mostly includes the physiological changes, one of which is the shortened growth of elongation towards keeping the carbohydrates and energy for production of the antioxidant regulations in rice plants. Furthermore, molecular studies and gene cloning might help suggest a better understanding of means and adaptations built-up by rice plants in order to stay alive and to remain active during flooding stress, might help to focus on some novel approaches to the up gradation as well as improvement on the natural cultivation of rice plants.

Arecanut or betel nut (Areca catechu L.), one of the most important economically cultivated plants of the family Arecaceae, is an unbranched, medium-sized or long, erect, monoecious flora growing in almost all arid and semi-arid tropical regions. Naturally, the species is exposed to various stresses when raised in nursery or in field planted conditions. The excess salinization of soil, which is more conspicuous by its presence in both arid and semi-arid regions, is one of the main factors limiting crop and agricultural outputs around the world

Rhizobacteria are root-colonizing, non-pathogenic, and their association with the roots of plant improves productivity and tolerance of abiotic stress such as heavy metal toxicity. Inoculation against biotic stresses also increases tolerance against heavy metal toxicity. Rhizobacteria might also increase nutrient uptake from soils that prevents the uptake and accumulation of nitrates and phosphates in agricultural soils. Also, some useful bacteria-mediated plants showed gene-expressions during plant-rhizobacteria interaction. Mining activities affect plant and health via water through: the method of extraction; contamination of local water sources as well as having harmful effects on the environment such as beach erosion from sand mining or by longer term effects on reducing microbial and biodiversity populations. Here, we review the current understanding of the physiological implications of rhizobacteria in the alleviation of heavy metal toxicity in plants, enabling cross-protection in agricultural advancement systems affected by growing climatic changes in natural conditions.

The deficiency of oxygen in water during submergence is one of the frequently perceived environmental factors that limits or hampers production of the rice cultivation. Rice plants comprise of elongated submerged tissues that help to bear with the rise of water level in natural location. This characteristic helps the plant to deal with flooding stress. The mechanism on flooding tolerance and adaptation mostly includes the physiological changes, one of which is the shortened growth of elongation towards keeping the carbohydrates and energy for production of the antioxidant regulations in rice plants. Furthermore, molecular studies and gene cloning might help suggest a better understanding of means and adaptations built-up by rice plants in order to stay alive and to remain active during flooding stress, might help to focus on some novel approaches to the up gradation as well as improvement on the natural cultivation of rice plants.

Today, different new methodologies have been adopted for the study of plants and their adaptation. Plant Biologist may choose a simple model for furthering the study of plants in science. Botanist studies more on the topics of Taxonomy, Genetics and Physiology. Ecology and of evidences on evolution are found in the comparative studies on anatomy, paleobotany, taxonomy, morphology and historical geography. In view of the rapid change in environment, molecular biology has become the most advanced biotechnology and has also created a green world in the study of plants. Botanists have exploited the techniques of molecular genetic analysis, including those of genomes and proteomics of DNA sequences, to classify plants more accurately. Further, genetic engineering in agriculture has introduced various new techniques for the purpose of genetic manipulation. It is one of the most advanced techniques in the modern world and will simultaneously be the most viable part of agriculture. Varshney et al reconsidered two key biotechnology approaches, i.e., molecular breeding and genetic engineering, and their amalgamation with conventional breeding to develop and increase crops that are more tolerant of abiotic stresses.

In natural environment, plants consist of both metabolic and tolerant mechanisms in toxic non-essential metals like Arsenic, Cadmium, Lead and Mercury. Natural activities composed of mining and smelting operations, including some haphazard practices in agriculture, have extensively contaminated some areas around the world—as for instances, in India, Japan, Indonesia and China by Cadmium, Copper and Arsenic and Copper and Lead in Greece. In fact, South-East Asia is suffering from the contamination of the groundwater Arsenic, as in the same way the existence of Copper, Lead, Nickel, Zinc and Cadmium is nothing new in some parts of Australia. Indeed, heavy metal contamination has become a worldwide problem. The uptake as well as accumulation of the aforesaid metals by plants is the main factor responsible for threatening the health of both man and animal into their food by toxic metals. The production of phytochelatins, a metal-binding thiol peptide and metallothionin, to react against the heavy metal stress may have provided for an appropriate metal tolerance in plants but needs a comprehensive study on it; for a better understanding on the different metal transports, their accumulations as well as over expressions in plants would definitely pave the better ways to develop metal tolerant plants or transgenics. Keeping the rising concerns over heavy metal stress affecting agriculture produce and plants in view in water; this review aims at throwing light as a tip on the iceberg about the physiological and biochemical mechanisms of metal accumulations, their responses and detoxification to the toxicity as well as to the metal stress tolerant plants.

The growth of scientific studies involving plants towards matching with the everincreasing demands of development is indispensible, at which our efforts on researchare aimed in line with the requirement. The interdisciplinary field that generatesdiscussion and research between environment and plant science including human-focused themes is highlighted in this article. In particular, the strategies to wipe out themain bottleneck of studies on plants are briefed so that they could be visualised by theprospective researchers in future.