eChapters

Growth and development are two important stages in a plant. Plant growth and development are under the control of both intrinsic and extrinsic factors. Growth is one of the fundamental characteristics of all living things. Even in Plants, the growth is visible but not measurable easily. Development in plants is actually a sum of two processes i.e. growth and differentiation.

Principles involved in plant growth and development: The various principles involved in plant growth and development are discussed below.

1. Totiopotency: Living plant cell has the potential to reproduce all the characteristics of the plant since it possesses all the genetic information.
2. Competence: It is the potential of cells or tissue to develop in a particular direction. Development of competency into a particular kind of cell(s), tissue or organ also may require special signals. These may originate internally within the plant or may originate externally as an environment signal, e.g. Internal change in type of growing point such as vegetative to flowering or initiation of adventitious roots on cuttings may be associated with a shift in the activity of specific hormones, external parameters i.e. application of growth regulators, or environment. It is mainly internal potential of meristem that gradually shifts from a vegetative shoot to one that produces flowers.

1. Choose the correct option for the characteristic of growth.

 a) It is an irreversible permanent increase in size of an organ or its parts or

even of an individual cell

 b)  It is accompanied by metabolic processes

 c) It occurs at the expense of energy

 d)  All of the above

2. Plant growth is unique because

 a) Plants bear the capacity for unlimited growth

 b)  Plants bear the capacity for limited growth

 c) Plants have diffused growth that differs from animals

 d)  None of the above  

Growth is a correlated increase in the mass of the body in definite intervals of time, in a way characteristic of the species i.e. increase in size and weight. This means growth includes the protein, fat and mineral deposition in the body. Growth is an irreversible increase in the metabolically active protoplasm. There is a characteristic rate of growth for each species and a characteristic adult size and development. Maximum size and development are fixed by heredity and nutrition is an essential factor determining whether this maximum will be reached. An optimum nutritional regime is the one which enables the organism to take full advantage of its heredity.

Once cells are obtained from a culture collection or isolated from animal tissue,, cells are put in the flask with growth medium. The cells are inoculated at a density of 104-105 cells/ml to get a concentration of 106 cells/ml or 105 cells/cm2 in a solid surface in 2-3 days because of nutrient limitation, accumulation of toxic metabolite or lacking of growth surface.

Growth of bacteria can be defined as change of total population mass, not individual increase in size or mass. Macroscopically visible growth of bacteria on the solid medium is known as ‘colony’. It is estimated that if Escherichia coli are allowed to grow, a single bacterial cell can produce a daughter population with the mass of the whole earth within 2 days! In the environment the bacteria are not actively growing all the time. The mechanisms behind the growth-arrested states of environmental bacteria are not well understood.

Bacterial reproduction

Bacterial reproduction is an asexual process which occurs by binary fission, budding, fragmentation and condiospore or sporangiospore formation. There is no possibility of genetic exchange (reassortment) as it is originated from a single parent cell. Bacterial gene transfer occurs by transformation, transduction and conjugation methods (discussed later in details). These are one-directional DNA transfer methods and are not associated with reproduction. The donor bacteria can give the genetic material to the recipient and the vice-versa does not occur.

Binary fission: In binary fission, bacterial DNA is replicated first and then the parent cell separates. Each daughter cell receives a complete genome, identical to the parent cell. Bacterial DNA replication begins when the cells reach a specific mass. If the cell diameter is constant, longer cells will begin DNA replication earlier than the shorter cells. The shorter cells need time to reach a critical mass required for the initiation of DNA replication. The ugtP proteins were identified to be associated with shorter cells and delayed DNA replication in Gram-positive bacteria (Bacillus subtilis). It was confirmed later that the ugtP act as inhibitor for Z-ring formation.

The term growth refers to an irreversible increase in size and weight of the plant. It normally reflects an increase in protoplasm, which may occur through increase in size of the cell and number of cells. Hence, the process of cell elongation and cell division provides the basis for growth. Cell division and enlargement are complicated processes involving synthesis of many organic compounds such as protein, cellulose and nucleic acid, besides the physical force required, which results in cell enlargement. The growth of the whole plant is compartmentalized into areas called ‘meristem’ where cell division and cell elongation are localized. The meristem cells such as shoot apex, root apex, cambium and the intercalary zones undergo repeated mitosis resulting in replication of DNA and nuclear material and finally the cell mass increases. Adjacent to this area of meristematic activity is the region of cell elongation, which phases in to the region of differentiation and maturation.

The increase in protoplasm (occurring in cell division and elongation) is brought about through a series of events in which water, carbon - di-oxide and inorganic salts are transformed into living materials. These events include (a) photosynthesis (production of carbohydrates) (b) nutrient absorption and translocation (uptake of water, nitrogen and other mineral elements) and (3) anabolism (synthesis of various materials produced in plant from the carbon fragments produced by photosynthesis and from the inorganic nutrients and water absorbed from the soil). The energy required for all these processes is provided by a catabolic process viz., respiration (degradation of sugars and fats to release energy). The net balance of anabolism and catabolism results in growth of the plant.

Limited availability of additional land for crop production, along with declining yield growth for major food crops, have heightened concerns about agriculture’s ability to feed a world population expected to exceed 7.5 billion by the year 2020. Decreasing soil fertility has also raised concerns about the sustainability of agricultural production at current levels. Future strategies for increasing agricultural productivity will have to focus on using available nutrient resources more efficiently, effectively, and sustainably than in the past. Management of the nutrients needed for proper plant growth, together with effective crop, water, soil, and land management, will be critical for sustaining agriculture over the long term. Plants, like all other living things, need food for their growth and development. Growth is the function of various factors like light, carbon dioxide gas, water and mineral nutrients. Plants require 16 essential elements. Carbon, hydrogen, and oxygen are derived from the atmosphere and soil water. The remaining 13 essential elements (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, zinc, manganese, copper, boron, molybdenum, and chlorine) are supplied either from soil minerals and soil organic matter or by organic or inorganic fertilizers. For plants to utilize these nutrients efficiently, light, heat, and water must be adequately supplied. Cultural practices and control of diseases and insects also play important roles in crop production. Each type of plant is unique and has an optimum nutrient range as well as a minimum requirement level. Below this minimum level, plants start to show nutrient deficiency symptoms. Excessive nutrient uptake can also cause poor growth because of toxicity. Therefore, the proper amount of application and the placement of nutrients are important.

1. Growth of plant pathogens

Various plant pathogens, namely fungi, bacteria, nematodes, viruses, viroids, mollicutes, fastidious bacteria, and protozoa, grow in different ways.

1.1 Fungi and parasitic higher plants

Fungal pathogens and parasitic higher plants usually invade and infect tissues by growing on or in them from the first point of inoculation.

Most of these pathogens, whether they cause small lesions or large infected areas on the plant, grow, branch, and spread to more and more plant tissues until the infection stops spreading or the plant dies.

Growth is a characteristic of life of any living being, and it continues until the end of organism. It is expressed in height, weight, volume, size, shape, number and area in every biological system. The shape and size of the plants are because of their continued cellular development and differentiation. Growth, which is quantified mathematically in terms of time, is termed as growth rate, and this gives a valuable information documenting growth as influenced by various abiotic, edaphic and biotic factors.

Principles

Various growth indices are better indicators of plant or crop performance under a specific treatment. Growth indices can be calculated from pot culture or field grown plants. Growth curve can be fitted using these values to predict productivity.

Requirements

Greenhouse or field-grown plants, scale, tags, hot air oven, electronic balance and leaf area meter are the basic requirements for recording the data on different parameters of growth.

Introduction

Rice plays a unique role in providing food to the majority of the world population. Rice is the most widely consumed food for nearly three-fourths of the population in India. Now a days scented rice is getting higher market price than normal rice varieties. Black Scented rice is commonly considered as forbidden rice. Different researches proved that black Scented rice is one of the “super food” of the world. Black Scented rice is consumed in various ways like puddings, pulao, bread, etc in different festivals and during important ceremonies. Mostly this crop is prone to lodging but resistance to infestation by insect and pest. Works done in India and abroad indicates that the particular method of establishment, adequate level of nitrogen and a particular time of application of nitrogenous fertilizer can enhance productivity. Nitrogen is the main nutrient that determines rice yield, due to its role in the photosynthesis, biomass accumulation and, spikelet formation (Hasegawa et al., 1994; Yoshida et al., 2006).

a) Large Unpenetrated Market
According to the sample registration system (SRS) baseline survey, 2014 released by the registrar general of India, 71 percent of Indians over the age of 15 are non-vegetarian.
b) Young Growing Population and Nutritional Security
India as a one of the major young population country in the world (27.4%) according to FAO, OECD 2018 data there is a huge need to address the nutritional security of the people with higher protein diet. Thus, we have high requirement of protein to feed country’s population in up- coming years.
c) Per Capita Consumption & Income
The annual per capita consumption of broiler meat and eggs for India is far below then recommended consumption of 180 eggs and 10.8 kg poultry meat per person per annum by Indian Council of Medical Research. The increase in per capita disposable income has led to an overall increase in food consumption, particularly protein in the form of meat and eggs.
(McKisney and company Report, 2013). The study conducted by Law et al. (2019) suggested that in India the consumer preference has changed and the cereals are now substitute of animal products rather than a complementary product

Regulations should make it easier to utilise creative, long-lasting solutions, allowing for the selection of the most environmentally friendly pest management method. This can be accomplished by using expedited registration, priority registration, and a combination of comparative evaluation of pest control techniques and the substitution principle, which allows a natural pest control technique to take the place of a synthetic pesticide.

Need of Bioinformatics

Bioinformatics, an emerging area offering a fundamental tool to the scientific community, to speed up the research, application and commercialization of biotechnology. In fact the best thing, which has happened towards the end of the 20^th century and in the 21^st century, is the marriage between biotechnologists and information technologists leading to the growth and development of this field. India took a lead as early as in the 1980s but more precisely from 1986 onwards by establishing a strong base of Bioinformatics with the necessary infrastructure. As a result one has seen major breakthroughs in biology and the growth of biotechnology has been phenomenal in the last decade, especially with the most outstanding technological breakthrough of the 20^th century wherein the draft human genome sequence was completed in 2000 and now the genetic code is completely sequenced. This has provided the worlds scientific community information on the vast sequence and structure of the Genomes, the crystal structures and there is an increasing dependence on computational approaches. Biotechnology has emerged as a front-line area with vital significance in unraveling secrets of life, particularly in the studies of new biology and biotechnology. The genomic revolution has underscored the central role of Bioinformatics in understanding the very basic of life processes.

The term growth as applied to higher organisms such as animals commonly is concerned with increase in protoplasmic mass and does apply to reproduction or to increase in number. In microbiology the term refers to increase in the number of organisms. Bacteria increase in number by a process of simple binary fission. Each cell increase in size and redivide into two similar cells. Each of the divide cells may in turn divide to become two cells. Each division produces what is termed as new generation of cells, theoretically there are 2,4,8,16,32,64,128,256 cells in the 2,3,4,5,6,7,8,& 9th generation, this is known as logarithmic growth – the population doubles with each successive generation. Under favourable conditions, bacteria produce generation within 15min. Under unfavourable conditions 24 hours of more may be needed for each generation. Generation time for E.coli is 17 to 20 minutes.

INTRODUCTION

Aquaculture is the fastest growing food producing sector with annual growth rate of 10.34% and it play a very important role in improving the income generation as well as nutritional security of farmers in many developing countries including India. In the fresh water system, carps are the most widely cultured species throughout the country and carp culture in India is believed to be as old as carp culture in China. Although in early years, carp culture was largely restricted to the North-Eastern States of India, during the last four to five decades, it has spread to almost all parts. The traditional carp culture practice is rapidly transforming into scientific farming in several parts of India. Generally, carp culture in India is a polyculture of 3-6 species of major carps and exotic carps (Vijay Anand, 2019), namely, catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhinus mrigala), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella) and common carp (Cyprinus carpio). Among six species, common carp (Cyprinus carpio) cultured in the composite fish farming system is potential species, which plays a vital role in the Inland Fish production especially for the North Eastern Hill states of India as the species has got high adaptability and tolerance towards high range of temperature and dissolved oxygen variation. The species is introduced to India in 1937 as the Prussian strain and in 1957 as the Bangkok strain. Due to their high food value, the farmers of the state have been culturing the fish in rice fields in monoculture or along with other species particularly in Apatani Plateau of Ziro area gaining an average weight 75g to 110g (Hussain et al., 2018).

The growth pole theory was developed by French regional economist, Francois Perroux, in 1955. He was concerned with the phenomenon of economic development and with the process of structural change. Growth pole is a central location of economic activity. It is an urban location where economic activity ignites growth and better quality of life in the urban periphery.

He attempted to explain how modern process of economic growth deviated from the stationary conception of equilibrium growth. His arguments were based on Schumpeter’s theories of the role of innovations and large scale firms.

In Schumpeter’s analysis, development occurs as a result of discontinuous spurts in a dynamic world. The cause of discontinuous spurts is the innovative entrepreneur whose activities take place in large-scale firms. These firms are able to dominate their environment in the sense of exercising reversible and partially reversible influences on other economic units by reason of their dimension and negotiating strength, and by the nature of their operations.

Scale of operations, dominance and impulses have close relationship to innovate. This is the most important feature of Perroux’s theory and leads to the concepts of dynamic propulsive firm and leading propulsive industry. The dynamic propulsive firm is relatively large and belongs to a relatively fast growing sector. It has a high ability to innovate and intensity of its interrelation with other sectors of the economy is important enough for the induced effects to be transmitted to them.

11.1 INTRODUCTION

Plant growth regulators have remained an important component in horticulture from time immemorial because they were effective means of quantitative as well as qualitative improvement in growth and development of crops. Plant Growth Regulators (PGR) are diverse group of organic compounds other than nutrients, produced artificially or by plants which in low concentrations promote, inhibit or modify the physiological process in plant. The term includes both naturally occurring phytohormones as well as synthetic compounds. These are produced naturally in higher plants, controlling growth or other physiological functions at a site remote from its place of production and active in minute amounts. Plant Growth Regulators are used in different forms like liquid, powder, paste etc. “Hormone” is Greek word derived from “hormao”, which means to stimulate. Thimone (1948) suggested the use of term ‘phytohormones’ as the organic substance, which are produced naturally in plants, synthesised in one Part And usually translocated to other part wherein every small quantity affects the growth and other physiological function of the plants. To distinguish them from the animal hormones they are termed as phytohormones. Auxin was the first hormone to be discovered in plants and at one time considered to be only naturally occurring plant growth hormone. The role of plant growth regulators in various physiological processes such as seed germination, f lowering, fruiting, seed development, fruit ripening and yield etc. in different crop plants is well established (Kiran et al., 2011). There are five classical phytohormones: auxins, gibberellins, cytokinins, ethylene and abscisic acid. Besides classical phytohormones a variety of other compounds that play roles in plant growth and development have also been identified, including jasmonic acid, salicylic acid, brassinosteroids and polyamines (Basra, 2000). The application of plant growth regulators in agriculture has started in 1930 in the United States. Ethylene, a naturally occurring substance, is one of the first plant growth regulators being discovered and used successfully for enhancing f lower production in pineapple (Fishel, 2006). Its toxic effects to human beings are low.

Growth and differentiation are regulated by a group of organic compounds known as growth regulators. These growth regulators regulate growth not only at the organ level but also in the plant as a whole. They can be broadly defined as organic compounds synthesized in one part of a plant transported to another where at very low concentration they cause a physiological response.

There are five major groups of growth regulators, namely, the Auxins, Gibberellins, Cytokinins, Ethylene andAbscisic acid. Endogenously synthesized growth regulators are often referred to as plant growth hormones. However, a number of synthetic compounds eliciting similar response as that of the growth hormones have been identified and extensively used. These synthetic hormones effectively substitute the endogenous hormones to understand the basic mechanisms of hormones and also for commercial use.

If frost has hit an orchard during winters, it does not always imply that permanent loss has occurred. Plants do possess natural protective mechanisms due to which they survive the stress to a variable extent depending upon their nature and organ being exposed to the stress.