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Classification refers to grouping of individuals with similar identities related to genetic make up, evolution or climatic requirements. The major units are order, family, sub-family, genus, species, variety/cultivar and strain. Monocotyledonous and dicotyledonous are two major classes and most of the fruits are covered under dicotyledonous family. Different basis of classification of fruits are: Botanical; Ecological; Stem morphology; Fruit morphology; Flowering habit; Respiration rate; Photoperiodism; Shade tolerance; Drought tolerance; Soil texture and topography; Soil reaction; Soil tolerance; Horticultural; Bearing habit; Inflorescence type; pollination types; Type of self incompatibility; Type of dichogamy; Edible parts; Center of origin; Ploidy levels; Longevity of fruit crops; Fruit size and Nutrient contents of fruits.

Vegetables are rich source of vitamins, minerals than other than nutrients. In India, vegetables occupy only 2.8% of the total cropped area. Vegetables are (except mushroom) grown for their succulent and edible parts such as the roots, stems, leaves, young tops, fruits or seeds which are used in culinary preparations either fresh or preserved in the fresh state.

These crops are further classified into different groupings according to similarities in edible parts, growth habits, methods of culture and botanical family.

Floriculture is the aesthetic branch of horticulture which deals not only with the cultivation of ornamentals, annuals, biennials and perennial plants but also with their marketing. Flowers symbolize beauty, purity, peace and love. In India, it is a dynamic and expanding industry showing an impressive annual growth rate.

Classification of Flower Crops

The flowering plants can be classified broadly on the basis of their species, genus, family, plant part used or type of flower plants. They are further classified as cutflowers, cut foliage, turfgrasses, groundcovers, hedges, accents, specimen plants, avenue trees, screens, topiaries, fillers and others.

Abscission: The shedding of leaves, flowers or fruits as a result of formation of layer of loosely adhering cells at base that breaks apart readily.

Accent: It is created in the garden to avoid the monotonous view. Mostly unusual object like tall fountain, tree, statue etc are used to create the effect

Acre: A unit of measurement of land area equivalent to 4840 square yards or 0.4047 hactare.

Acropetal: Developing sequentially from basal to the apical position.

Acrylic: It is a glassy thermoplastic that is incorporated in rigid plastic to enhance wither ability.

Aestivation: The use of high temperature to promote flowering.

After-ripening: Physiological changes that take place within a dormant seed or bud during dormancy or It is a type of embryo maturation which enables germination of seeds.

Edaphology is the study of soil properties in relation to plant higher production.

Pedology refers to study of origin of soils in their natural environment, classification and description.

pH is the negative logarithm of the concentration of H+ ions in soil solution.

Soil profile is a vertical exposure of horizon sequence.

Soil texture is not changed by cultural management.

Cation exchange capacity (CEC) is defined as sum total of exchangeable cations that a soil can absorb.

1. Chlorophylls

Chlorophyll can be regarded as a true representation of health of green plants. This presumption is based on the fact that chlorophyll is most commonly and immensely influenced by biotic and abiotic stress conditions in addition to events like pathogenic invasion, pollution, mineral deficiencies as well as mineral toxicity. This is the reason that estimation of chlorophyll is considered to be one of the most important parameters in plant physiological studies.

Eukaryotic plant cells possess many types of ‘reserves’, one of them is plastid. A plastid, that contains green colour is known as chloroplast and the green colouration of a chloroplast is mainly due to the presence of a pigment to which we call as chlorophyll. Normally, chlorophyll constitutes about 4% of chloroplast dry weight.

Chlorophyll ‘a’ and ‘b’ are the most abundantly found in all autotrophic higher plants. However, there are other chlorophylls also such as ‘c’, ‘d’, ‘e’, bacteriochlorophyll and bacterioviridin which have restricted presence in blue-green, brown and red algae.

A chlorophyll molecule contains ‘Tetrapyrrole’ skeleton formed into a ring with an atom of magnesium (Mg⁺⁺) in the centre. A so-called ‘Pyrrole’ molecule contains four carbon and one nitrogen atoms arranged in a ring. Four such pyrrols arranged in a ring form the ‘Head’ of chlorophyll molecule. Attached to this is ‘porphyrin ring’, at one point, is a ‘phytol’ tail- a long chain of linked carbon.

The weight of living plant material contained above and below a unit of ground surface area at a given point of time, is known as plant “Biomass”. Biomass is of utter importance because it provides energy source (Roberts et al. 1987).

Biomass, which has dimensions of mass per unit, is expressed as g m^-2, kg ha^-1 or t ha^-1.

Measurement of Biomass

The area (in the crop field) under study is divided into a number of equal squares or rectangular plots measuring 1.0 m² or 0.5 m². Each square is designated with a particular number. Sample can be harvested from a small area or quadrate at the centre of each square; the remaining peripheral area serving as buffer zone (Wiegert, 1962).

Depending upon the growth pattern of plant species two different designs have been adopted for the sampling:

Growth represents overall performance of a plant under a particular environment. Generally, we restrict to the above ground plant parts for growth studies, however, a better understanding of plant growth and development would be achieved if total dry matter (including above ground shoot as well as underground root) were taken into consideration.

The basic principles behind growth analysis constitutes (i) data on plant height and (ii) leaf area. The quantitative analysis of growth is based upon several terms, which are described below (Hunt, 1978).

1. Growth

Growth is an irreversible increase in size which may or may not be accompanied by an increase in dry weight. It is the sum total of all the metabolic activities and normally results from the excess of anabolism over catabolism. In general, it refers to quantitative changes in the life cycle of plants. However, there are a few examples where growth is not accompanied by an increase in dry weight such as (i) germinating seeds and, (ii) etiolated plants.

1. Relative Water Content

Relative water content (RWC) is an important parameter to measure the water status of plant tissue. High RWC, under moisture stress, denotes ability of plants to tolerate drought. (Ritchi et al. 1990). RWC and water potential have often been reported as indicators of drought tolerance (Schonfeld et al. 1988).

Leaf water status may be estimated by measuring the RWC following Barrs and Weatherlay’s (1962) method as given below:

The most abundantly and commonly available compounds in the plant kingdom are carbohydrates. They comprise saccharides viz.

Monosaccharides - glucose, fructose etc.

Disaccharides - sucrose, lactose, maltose etc.; and

Polysaccharides - starch, cellulose etc.

Cellulose is the major component of plant cell wall.

The active groups in carbohydrates are aldehyde (-CHO) and ketone (=CO). In addition, they contain hydroxyl groups as well. The chemical properties of saccharides vary depending upon the number of hydroxyl groups and the presence or absence of (–CHO) or (=CO) groups.

Plants take up nitrogen from soil either in the form of nitrate or ammonia. Nitrate taken by plants is reduced by nitrate reductase and nitrite reductase enzymes. They catalyze step-wise reduction of nitrate to nitrite and nitrite to ammonia. Ammonia occupies the key position in nitrogen metabolism for the synthesis of organic nitrogen. Glutamic acid dehydrogenase, GOGAT and GS are important enzymes which are involved in the conversion of ammonia into glutamic acid, a primary amino acid. The ?-amino group of several amino acids is formed as a result of transamination reaction through transaminase/ aminotransferase enzymes. This process is of great significance in amino acid metabolism.

1. Protein Estimation

The method developed by Lowry et al. (1951) is largely followed for the estimation of soluble protein. This method is quite sensitive and gives a moderately constant value.

Protein may also be estimated by analyzing the total nitrogen content. Multiplying total nitrogen value with 6.25 will give the crude protein content. However, the nitrogen per cent varies with amino acid composition of proteins. For more refined expression of protein percentage, different factors are used for different samples. Some of the conversion factors for cereal and oilseed are given below: