eChapters

Twitching is a condition occurring predominantly on the surface of the fruit which is exposed to direct sunlight; however, it is not well understood what the source of the disease is. Growth in immature fruits cannot be detected during later stages of fruit maturity. On cv. Golden Solo Party there are a few examples. This is termed the “frog skin” or “fox skin.” It shows on the fruit’s surface as the Dark Brown Flecks. 

Ordinarily, fruit bears a single crown, but fruit bears more than one in some cases. The top of the fruit will therefore be smooth and wide and the fruit will not be ideal for canning. These fruits have an insipid taste and are corky. It is intended to be an inherited character, often found in the Cayenne group to which the Kew variety belongs.

Pineapple, are well adapted crops for the farmers towards water economy due to its morphological, anatomical, and physiological characteristics. However, the plant contains rosette leaf structure can able to channels the light rainfalls and dew through stem and finally into the soil. It also have the ability to absorb water and nutrients through their waxy leaves and aerial roots and can capable to store water in specialized aquiferous leaf tissue; multicellular trichomes that cover the leaves and protect the plant from excessive transpiration by reflecting radiation; a thick cuticle covering the leaf epidermis that restricts water loss by evaporation, location of the stomata in furrows at the lower leaf surface where they also are covered by trichomes, limiting evapotranspiration; and its nocturnal carbon dioxide fixation via the crassulacean acid metabolism (CAM) carbon assimilation pathway, which results in stomatal opening primarily at night when evaporative demand is lowest (Reinhardt et al., 2018). The most common propagating material of pineapple is suckers or slips. Suckers are used to arise from the underground parts of the plant are used for propagation. Slips arise from the fruiting stem and the crown region on top of the fruit.

In this context, it is important to know the nutritional aspects of pineapples which are as attractive as their unique anatomy. “Pineapples contain high amounts of vitamin C and manganese,” said San Diego-based nutritionist Laura Flores. These tropical fruits are also important for the dietary fiber and bromelain (an enzyme). “As well as having high amounts of manganese, which is important for antioxidant defenses, pineapples also contain high amounts of thiamin, A, B vitamin that is involved in energy production,” Flores said. Pineapples are fat-free, cholesterol-free and low in sodium (Arpaia et al., 2004; De Costa, 2010). Side by side they contain sugars of about 14 grams per cup (www.livescience.com, 2019). In continuation with this, the chapter was focused on physiological disorder of pineapple caused by various reasons.

Basically, non-pathological conditions are the reasons of physiological disorders of any kind of crop plants; it includes poor light, adverse weather, water-logging, phytotoxic compounds or a lack of nutrients, which affects the normal functioning of the plant system. Sometimes physiological disorders may be initiated before harvest, continue their development after harvest, or appear after harvest. In was observed several times that physiological disorders are causative agent for the deterioration of horticultural commodities which leads to economic losses. An important commercialized fruit i.e., pineapple is also facing the same problem of different kind of physiological disorders; it includes multiple crowns, fruit and crown fasciation, collar of slips, dry fruit and bottle neck, sun-scald/ sunburn, blackheart etc.

Fruit cracking is a serious problem of pomegranate (Punica granatum L.) particularly in arid climate. Cracked fruits are sweet but unfit for long distance transportation. Incidence of cracked fruits varies from 10 to 70 % depending upon the prevailing environmental conditions. Longitudinal or radial splitting of rind surface occurs.

There is secondary elongating growth in the roots that gives a form of fork like structure to the root. This occurs in heavy soil due to soil compactness. An elongated radish root is encouraged by un-decomposed organic manure. It can be fixed by decreasing field moisture, balanced irrigation and also by sowing radish and carrot in sandy loam or light soil with loose and friable soil in nature.

The normal blooming stem on the greenhouse rose has fully developed sepals, petals and reproductive organs. The inability to build a bloom at the apical end of the stem is a typical phenomenon which in such shoots is termed blind. There are sepals and petals; however, they are not complete or aborted in the reproductive portions.

Blossom end rot is a very common problem on green and ripe tomatoes. It started with light tan, water-soaked lesion, and then increased to black and tough. Although blossom blight itself caused only local damage, secondary biological invasions frequently lesions caused fruit rot complete.

Symptoms of pale or yellow-green leaves (chlorosis) first occur in the older leaves. At the leaf margins reaching toward the midrib or central vein, reddish tints gradually emerge. The leaves are thin. Growth overall is markedly reduced. Deficiency results in rhizome yield loss.

In addition to pathogenic diseases, numerous abiotic disorders may also arise during growth, development and post-harvest storage of solanaceous vegetables. The physiological disorders of vegetables that have been included in this chapter are directly or indirectly associated with genetic, cultural, nutritional, physiological and environmental factors, and in most of the cases, the definite cause of disorder is not well understood due to the association of numerous factors together. These disorders may be related to colour, shape and form/condition of the produce. The genesis of physiological maladies was earlier poorly understand due to complexity in their characteristic symptoms but at present is relatively more transparent. The characteristic symptoms of abiotic disorders discussed below have not been attributed solely to a single agent or to a single cultural or environmental factor. The environmental factors correlated with the incidence of these disorders include high light intensities and low or high temperature of that growing area. For many abiotic disorders, very limited research work has been done, and the causes are poorly understood both in terms of why cultivars differ in susceptibility and why certain environmental factors predispose the plants or parts of the plant to the disorder. The growers feel concerned with the incidence of abiotic disorders as these cause huge economic loss. Therefore, the control of these abiotic disorders is essential for profitable production of solanaceous vegetable crops. In this chapter, emphasis has been given on practical aspects of diagnosis and potential control measures.

DEFINITION

Plant disease in which no pathogens or parasites is associated with the cause is known as Non-parasitic disease. They are also called as non-infectious or physiological disorders. When no pathogen is found, cultured from or transmitted from a diseased plant, then the disease is said to be caused by a non-living or environmental factor. These diseases occur because of disturbances in the plant system by the improper environmental conditions in the air or soil or by mechanical influences.

Introduction

The physiological disorder of a mineral nutrient is entirely contingent upon its function within the plant body. Inadequate or excessive supply of any essential element can result in metabolic disruptions, influencing the activities of enzymes, rates of metabolic reactions, and concentrations of metabolites. Alongside alterations in metabolic patterns, severe deficiencies of specific essential elements also give rise to distinctive effects in leaves, stems, roots, blossoms, and fruits.

A. Nitrogen

Functions: Nitrogen is essential for plants, playing crucial roles in protein synthesis, nucleic acid formation, and chlorophyll synthesis. It is a key component of enzymes, contributing to various metabolic processes. Nitrogen also supports root development, cell structure, and the synthesis of secondary metabolites. Striking a balance in nitrogen levels is vital for maintaining plant health and ensuring optimal growth and productivity. Effective nitrogen management is essential for sustainable agriculture and overall ecosystem well-being.

Harvesting is one of the agronomic management practices that require technical knowledge on maturation of the crops. This knowledge is much important in seed production than in commercial production.

Physiological maturation

• It is the stage of accumulation of maximum dry matter within the seeds. The moisture content of the seed at this stage will be in decreasing order (25-30%) and is expressed with maximum dry weigh of seed, germination and vigour potential. The physiological maturation is represented for individual seed and this maturation will not be the same for the population, due to differential flowering habit.
• The attainment of physiological maturation is represented by sigmoid curve of growth pattern. The physiological maturation can be represented both as duration and visible symptoms.

Introduction

In the past few decades, persistent change in climatic variables coupled with global warming lead to the genesis of climatic stress. Currently climatic stress is considered as the most serious ultimatum to livestock’s growth, development, production and reproduction in tropics and subtropics including India. Livestock’s in tropical countries are most commonly affected by the menace of climatic stress. It has been shown that, climatic stress upsets animal’s body homeostasis resulting in grievous decline in livestock’s production and productivity across the world. In general, livestock adapt to the climatic insults via behavioural, physiological, biochemical, metabolic, endocrine and molecular responses. Despite of these thermal adaptation mechanisms, livestock’s witnesses the perils of climatic stress thereby incur major loss in their production and productivity. Therefore, in this changing climatic scenario, it is imperative to rigorously understand and explore the precise mechanism of thermal adaptation to generate climate resilient species which could upsurge the socio-economic status of the farmers as well as the country.

Stress is force per unit area. When matter is subjected to stress; it may undergo changes in size, shape and displacement. Plants are grown in open environment and are likely to experience stress due to environmental conditions or when subjected to pests and diseases. The stress experienced by plants due to environmental conditions is called abiotic stresses. These include stresses caused by weather factors and climatic conditions and include moisture stress and thermal stress. The plants may also experience stress due to strong winds, dryness and as well as humid conditions (Fig.8.1).
The plants are generally classified into three types depending upon the ability to cope up with moisture stress as exhibited by-
• Drought resistance
• Drought tolerance
• Drought adaptations
The moisture stress may be to shortage of Water Compared to its requirements for evapotranspiration and metabolic activities. The plants may also suffer moisture

Introduction: N metabolism

Nitrogen is one of the three essential macronutrients for plant growth and yield (Su et al., 2005) and most crucial elements for root growth also (Fageria, 2014). Most macromolecules and a variety of secondary and signalling substances, such as proteins, nucleic acids, cell wall components, hormones, and vitamins, contain nitrogen (N), an important element. In order to assimilate nitrogen, nitrate must be reduced to ammonium, and then ammonium must be converted into amino acids. Perez et al. (1973) pointed out that the rice genotype with high protein yield translocated N from leaf blade to the developing grains more efficiently than the low protein genotype. This was reported due to a high concentration of free amino acids in the sap translocated to the developing grains rather than to differences in translocation rates. Therefore, proper understanding of N metabolism and amino acid translocation are prerequisite to comprehend higher grain protein in high yielding rice genotypes. Use of N by plants involves several steps including uptake, assimilation, translocation and remobilization; and recycling and remobilization when the plant is ageing (Fig. 1). The enzyme nitrate reductase (NR) assimilates nitrate, the main form of nitrogen available to agricultural plants in the field. This enzyme and the nitrogen status of various higher plant systems have a strong positive link, and growth, yield, or protein content can occasionally be connected to this enzyme’s level in seeds or leaves. Nitrate intake occurs at the root level, and it has been demonstrated that plants have two nitrate transport systems that work together to cohabit, absorb, and distribute nitrate from the soil solution throughout the entire plant. (Srivastava 1980) Following NO3- uptake by NO3- transporters and reduction of NO3- to NO2- by nitrate reductase (NR) in the cytoplasm, the process of NO3- assimilation commences (Lea and Miflin, 1974).

Introduction

The life cycle of a plant passes through biotic and abiotic stresses and plants are being attacked at different stages of growth by a number of disease causing organisms. These organism including bacteria, fungi, viruses, and nematodes attacks plants. These pathogens caused large crop losses and probably since the beginning of agriculture have contributed to human hunger and malnutrition. The control of plant diseases is thus of fundamental importance and is a major objective of plant breeding and pathology programme and agriculture chemical industry. Plants resists pathogens attack both with preformed defenses such as antimicrobial secondary compounds and by inducing defense responses (Hammond and Jones, 2000, Heath, 2000). Inducible defenses can be activated upon recognition of general elicitor such as bacterial flagellin and even host cell fragments released by pathogens damage (Gomez and Boller, 2000, Hammond and Jones, 2000). However, plants also involved sophisticated recognition systems to detect proteins produced during infection by specific races of pathogens (Martin et al., 2003).

Fruit ripening is a phenomena during which horticulture produce undergoes a series of complex physical and biochemical changes initiated through a series of hormones (Ethylene, auxin, abscisic acid (ABA), gibberellins, jasmonic acid, etc.) to attain maximum physiological maturity and favourable organoleptic properties. These changes lead to alterations in colour, texture, aroma, flavour and nutrient composition. In a nut shell, ripening involves increase in pulp to peel ratio, solubilisation of pectic substances, degradation of complex carbohydrates, organic acids and chlorophyll, accumulation sugars, flavour volatiles, polyphenolic compounds and pigments (carotenoids, xanthophylls and anthocynanins). The extent of these changes guide harvesting, readiness for processing and consumption decisions, with physic-chemical alterations serving as indicators of optimum ripeness. Respiration rate, ethylene and ABA are key regulators of fruit ripening in climacteric and non-climacteric fruits, respectively. In climacteric fruits, ABA interacts with ethylene, influencing the synthesis of ethylene itself. Although there is ample documentation on the involvement of hormones in fruit development and ripening, our understanding of the functions of various hormones throughout growth, maturation, and specific ripening processes remains incomplete.

Perennial fruit trees build their woody architecture with some building blocks, i.e. modular units, known as metamer or phytomer (White 1979; Room et al., 1992; Hare Krishna, 2012). It consists of meristems initially an apex. When a meristem faces periods of dormancy during low temperature or pruning, later it appears as bud, whenever active, as such bud produces a growing point with sequence of meristematic tissues simultaneously called a sprout, i.e. extension unit or growth unit (Halle et al., 1978; Bell, 1991). The driving mechanism behind the pattern appears to be auxin production (and basipetal transport) when new shoots and leaves developed and are exposed to light (Sterck, 2005). Other feature of trees are to produce more xylems relative to phloem, accumulate xylem over time and may thus produce thick woody branches and stems. Further, attaining reproductive phase and reproduction processes compete with vegetative functions, depleting resources necessary for maintenance and growth (Fakhri et al., 1987).

The idea that reproduction, growth and defence interact within the individual and compete for limited resource is now considered an established principle. Because there are trade-offs between a plant’s various functions and the concept of source, and sink helps to explain allocation patterns at both the physiological and evolutionary levels. Logical approaches have extended this hypothesis to an explicit as source and sink framework in which the effects of defence allocation on rates of consumption can be weighed against the effects on growth (Coley et al., 1985; Mooney and Gulmon, 1982; Fakhri et al., 1987). The allocation to vegetative structures has compounding interest for plant growth, as plant life-cycles begins with pure vegetative growth (Abrahamson, 1979), also consistent with the idea that perennials must forego some reproductive expenditure to retain sufficient resources for perennation.

Introduction
Ageing, a multifaceted and intricate process, is characterized by a series of transformations that occur at various levels of biological hierarchy, ultimately culminating in death. This phenomenon, marked by its complexity, involves numerous factors that interact simultaneously and operate across different levels of functional organization. The diversity of ageing phenotypes among individuals of the same species and the disparities in longevity
among different species underscore the significant roles of both genetic and environmental influences in shaping the lifespan.At its core, ageing is an ontogenic journey—a process of growing old that encompasses all physiological, genetic, and molecular changes occurring from fertilization to death. The biology of ageing pertains to the progressive accumulation of random molecular defects within tissues and cells, leading to age-related functional impairments in tissues and organs. This relentless, deleterious, and intrinsic phenomenon was famously described by Medawar in 1952 as an “unsolved problem in biology.” Despite the enduring mystery of the ageing process, research has advanced significantly since Medawar’s time, expanding our understanding of this intricate biological conundrum.
Goldberger et al. (2002) define senescence as the progressive deterioration of bodily functions over time, noting that normal human ageing is associated with a loss of complexity in various physiological processes and anatomical structures. Although ageing and senescence are often used interchangeably, they encompass distinct concepts. Senescence refers to a post-maturational process that leads to diminished homeostasis and increased vulnerability to death, while ageing encompasses any time-related process that begins at conception and continues until death. The mechanisms driving ageing are partially intrinsic, influenced by genetic and epigenetic factors, and partially extrinsic, shaped by environmental factors such as nutrition, radiation, temperature, and stress. Genetic factors account for approximately 25% of the variance in human lifespan, with the remainder determined by nutritional and environmental influences.