Environmental Plant Physiology

Botanical Strategies for a Climate Smart Planet

Vir Singh

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780367030421
• eBook ISBN: 9781000024906
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

Magnitude and quality of life as well as sustainable human progress inescapably depend on the state of our environment. The environment, in essence, is a common resource of all the living organisms in the biosphere as well as a vivacious basis of the evolution of life on Earth. A sustainable future broods over a sustainable environment—an environment encompassing life-originating, life-supporting, and life-sustaining uniqueness. A deteriorating environment haplessly sets in appalling conditions leading to shrinkage of life and a halt in human progress. The current global environment scenario is extremely dismal. Environmental disruptions, largely owing to anthropogenic activities, are steadily leading to awful climate change. Horribly advancing toward mass extinction in the near or distant future and posing a threat to our Living Planet, the unabatedly ongoing climate change, in fact, is an unprecedented issue of human concern about life in the recorded human history.

How to get rid of the environmental mess and resolve environmental issues leading to climate change mitigation is the foremost challenge facing humanity in our times. There are several measures the whole world is resorting to. They are primarily focused on cutting down excessive carbon emissions by means of development of technological alternatives, for example, increasing mechanical efficiencies and ever-more dependence on clean-energy sources. These are of great importance, but there is yet a natural phenomenon that has been, and will unceasingly be, pivotal to maintain climate order of the Earth. For it to phenomenally boost, we need to explore deeper aspects of environmental science. It is the environmental plant physiology that links us with deeper roots of life.

Environmental Plant Physiology: Botanical Strategies for a Climate-Smart Planet attempts to assimilate a relatively new subject that helps us understand the very phenomenon of life that persists in the planet's environment and depends on, and is influenced by, a specific set of operating environmental factors. It is the subject that helps us understand adaptation mechanisms within a variety of habitats as well as the implications of the alterations of environmental factors on the inhabiting organisms, their populations, and communities. Further, this book can also be of vital importance for policy makers and organizations dealing with climate-related issues and committed to the cause of the earth. This book can be instrumental in formulating strategies that can lead us to a climate-smart planet.

Features:

• Provides ecological basis of environmental plant physiology

• Discusses energy, nutrient, water, temperature, allelochemical, and altitude relations of plants

• Reviews stress physiology of plants and plants' adaptations to the changing climate

• Examines climate-change effects on plant physiology

• Elucidates evolving botanical strategies for a climate-smart planet

1	Environment and Ecosystems Physiological Basis of Ecology

Folks are like plants; we all lean toward the light.

Kris Carr

THE LUMENOSPHERE

What is the all-pervading factor in the universe that is also a key factor in the creation of life on Earth and which is the original source of all kinds of energy? It is light. This universe, in essence, is a home of light we can call lumenosphere (Latin: lumen = light; sphere, from Latin sphaera = globe, or range of a thing). It is not a thing that works. What works is a non-thing, that is, energy. It is the non-thing that makes the things work. All forms of energy in the universe emanate from light. The lumenosphere (or photosphere) accommodates countless galaxies, and each galaxy accommodates countless stars, and each star generates an infinite amount of radiation by means of nuclear reactions. And it is this radiation that illuminates the whole of its “home”—the lumenosphere—and keeps it going on.

The lumenosphere is not static in itself. Nothing, in fact, is static in the lumenosphere. The lumenosphere and everything in it is always in evolution. Evolution is a cosmic phenomenon that holds everything in the state of dynamism. Evolution, however, does not keep going on, on its own. It is triggered and propelled by the input of the energy of light. Things do not change on their own. There can be no change without energy. It is the energy that holds everything in a changing mode. The change is not random, abrupt, or directionless, or without a purpose. It has a rhythm, a definite direction, a hierarchical order, a purpose (Singh 2019). Such a change is what is called evolution. Evolution is a universal phenomenon. The lumenosphere is not just a physical dimension embracing all dimensions of existence. It is also a phenomenon in itself. Light is not just a form of energy comprising wave and particles (photons), it is a phenomenon, in fact, a phenomenon of all phenomena.

One of the phenomena of cosmic light is the biosphere. Powered by light, the biosphere itself is a living phenomenon of life. Reverberating with life, the biosphere is a living, perhaps the only living, oasis of the lumenosphere. Light is the only non-thing factor that has power to synthesize life within the biosphere—through a process known as photosynthesis. The other source of synthesizing life is chemical energy in some compounds, and the phenomenon associated with it is called chemosynthesis. Since the chemical energy is also rooted into the energy of light, chemosynthesis is also an indirect form of photosynthesis. It is through photosynthesis and chemosynthesis and energy in the organic molecules synthesized by these processes that the biosphere of the lumenosphere is replete with innumerable varieties of living organisms (have a glance at Figure 1.1). The diversity of life the biosphere accommodates is one of the most wonderful aspects of the lumenosphere. Our Living Planet and we all are part of this cosmic phenomenon. Environmental physiology helps us understand the phenomenon of life in the biosphere of Earth.

FIGURE 1.1 The cosmos as a lumenosphere. The biosphere of the earth—where solar energy flows in living organisms—is a “living oasis” of the lumenosphere.

THE BIOSPHERE

All ecosystems comprising a variety of communities of plants, animals, and microorganisms of the earth are integrated into a single stratum called biosphere. Biosphere (Greek: bios = life, sphaira = sphere) is the sphere or stratum of Earth’s surface extending from a few kilometers into the atmosphere to a few kilometers into seas and oceans that supports and sustains life. The biosphere comprises biotic components (the living organisms) and the physical environment (abiotic components) that support life. The relationship between the biotic and abiotic components is reciprocal. Credit of the development of the term biosphere goes to English geologist Eduard Suess (1831–1914) and Russian physicist V. I. Vernadsky (1863–1945).

The biosphere includes parts of all the three components of the earth, viz., lithosphere, hydrosphere, and atmosphere and, in essence, is the sum of all the ecosystems of the earth. The biosphere is solar-powered and capable of converting solar energy into biochemical energy by means of a marvelous phenomenon called photosynthesis. Chlorophyll-containing plants, algae, and cyanobacteria are empowered to transform sunlight into biochemical energy, the energy of life. All animals, parasitic plants, fungi, and several unicellular organisms depend on photosynthesis directly or indirectly. There is yet a variety of microorganisms capable of transforming the energy of inorganic molecules into the energy of life through another spectacular phenomenon called chemosynthesis. There is a wonderful community around hydrothermal vents deep down in the oceans and seas exclusively dependent on chemosynthesis. The biosphere, thus, functions through photosynthesis and chemosynthesis. In other words, the biosphere is the only “home” to life in the universe that accommodates the phenomena of photosynthesis and chemosynthesis, the bases of all life on Earth.

In the biosphere, biotic and abiotic factors are in constant interaction: abiotic (inorganic) components become integral parts of the biotic (organic) components and vice versa. There is constantly a considerable exchange of matter between the two components. As a result, the living organisms do not just bear structures but are also a phenomenon in themselves, maintaining their structures through the exchange of matter with the physical environment. The physical environment includes the climatic factors that operate thermodynamics of the biosphere conducive to the phenomenon of life. The biosphere, stating differently, is a phenomenon in itself operationalizing the abiotic–biotic phenomenon of life.

The biosphere blossoms with enormous biodiversity. Prokaryotes (like bacteria), single-celled eukaryotes (like protozoa), fungi, plants, and animal species prospering within a variety of ecosystems of the biosphere, are estimated between 3 and 30 million, out of which some 1.4 million have been identified. Again, the intraspecies (genetic) diversity is also implausibly high. The biosphere is never in a static state. It is charged with the power of natural evolution. Hierarchical life, systems, and orders are all the spectacular outcomes of an unceasing evolution. Biodiversity, also a splendid feat of natural evolution, is organized into ecological groupings, such as populations of different species and communities. Biodiversity of life at every level comprises the richness of life and sum total of this richness and the factors and phenomena upholding, evolving, and sustaining the richness of life constitute the biosphere.

THE ORGANISM-ENVIRONMENT RELATIONSHIPS

An organism constitutes the smallest level of ecological hierarchy. It may be unicellular or multicellular in its structure but is an “autonomous” unit of the environment capable of performing its own functions. An organism, however, is not an independent entity. For its existence, sustenance and other essential activities, it depends on several other organisms directly and indirectly. All the organisms on planet Earth constitute a biotic component of the environment. They all are in continuous interaction with their physical environment (abiotic component of the environment). There is continuous exchange of materials between the organisms and their physical or abiotic environment. They derive energy, nutrients, water, and oxygen from the environment, which is indispensable for their maintenance, growth, and reproduction. They return to their environment whatever is over and above their maintenance, growth, and reproductive functions. These include the heat and solid, liquid, and gaseous wastes generated through metabolism.

The environment is an integrated whole. The abiotic and biotic components are woven into each other and are inseparable from each other. The quality of the physical environment has implications on the living organisms. And the living organisms have bearing on the quality of the physical environment. The two are in a reciprocal relationship. All the factors operating within the physical environment as well as all the living organisms in an environment are in interactions with each other. The study of the relationships/interactions among living organisms and between their abiotic and biotic components in the environment, called ecology, is an interesting subject to understand the overall processes of life, including dynamic equilibrium, environmental physiology, adaptation mechanisms, ecological evolution, community organization, ecosystems, biomes, and the nature of the biosphere.

The complex interactions between biotic and abiotic components (Table 1.1) in the environment determine the overall state of the environment. Organisms perform normally amidst appropriate environmental conditions set due to the abiotic–biotic interactions.

Biotic and abiotic components are held in dynamism. The matter alternates between abiotic and biotic components. For example, carbon gets incorporated into biomass through photosynthesis and becomes part of the biotic component. Nitrogen molecules get fixed into proteins and become part of the biotic component. Upon decomposition of the biomass, carbon (as CO₂) and nitrogen (N₂) again return to the abiotic component of the environment.

The interactions between abiotic and biotic components in an ecosystem determine which species can survive and sustain in a given ecosystem and also how the species have evolved in and adapted over time to that environment.

TABLE 1.1
Components of the Environment

Abiotic Components	Biotic Components
Climatic Factors	Green plants (photosynthesizers)
Radiation	Non-green plants
Heat	Symbionts
Temperature	Parasites
Atmospheric gases	Animals
Edaphic Factors	Human beings
Soil formation	Decomposers
Soil composition	—
Soil types	—
Soil profile	—
Physical properties of the soil	—

ENERGY AND NUTRIENT FLOWS THROUGH ECOSYSTEMS

A community occupying an ecosystem is self-reliant and self-sustainable. This is possible through nutrient and energy flows among organisms within an ecosystem. Ecosystem organisms can be categorized into producers, consumers, and decomposers.

Producers synthesize carbohydrates using abiotic resources, viz., atmospheric carbon dioxide and water, through photosynthesis and chemosynthesis. In photosynthesis, chlorophyll-containing plants, algae and blue-green algae (cyanobacteria), use the energy of light. In chemosynthesis, a variety of micro...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Acknowledgments
• Author
• Chapter 1 Environment and Ecosystems: Physiological Basis of Ecology
• Chapter 2 Energy Relations
• Chapter 3 Nutrient Relations
• Chapter 4 Water Relations
• Chapter 5 Temperature Relations
• Chapter 6 Allelochemical Relations
• Chapter 7 High-Altitude Physiology
• Chapter 8 Stress Physiology
• Chapter 9 Physiological Effects of Climate Change
• Index