(a) Explain the properties and functions of enzymes in plants. (10 marks) (b) Write the methods of production of seed tubers…

(a) Enzymes: Properties and Functions Enzymes are biological catalysts, primarily proteins, that accelerate biochemical reactions in plants without being consumed. Their defining properties include high specificity, where an enzyme acts on a particular substrate or reaction type, and sensitivity to environmental factors like temperature and pH, which can denature their active sites. They lower the activation energy without changing the equilibrium of a reaction, catalyse reversible reactions, show saturation (Michaelis–Menten) kinetics, can be inhibited competitively or non-competitively, are regulated allosterically, and many require cofactors (metal ions such as Mg²⁺, or coenzymes such as NAD⁺) for activity. Functionally, enzymes are central to plant metabolism. RuBisCO catalyzes carbon fixation in the Calvin cycle, driving photosynthesis. Cytochrome oxidase facilitates electron transport in respiration, releasing energy for growth. Nitrogenase of Rhizobium bacteroids in legume root nodules fixes atmospheric nitrogen into ammonia, which the plant assimilates through glutamine synthetase and glutamate synthase; nitrate reductase begins the use of soil nitrate. Hydrolases such as α-amylase mobilise seed reserves during germination. Furthermore, enzymes like IAA oxidase regulate hormone levels, controlling growth patterns. Understanding these mechanisms allows for targeted interventions in crop physiology and stress tolerance.

(b) Production of Seed Tubers from True Potato Seeds (TPS) The production of virus-free seed tubers from True Potato Seeds (TPS) under protected cultivation follows a structured protocol to ensure genetic purity and health. TPS of recommended hybrid populations (such as HPS-I/13 and CPRI's 92-PT-27) is sown in raised nursery beds of soil and farmyard manure (about 1:1) inside an insect-proof net house (40–50 mesh), which excludes aphids that spread viruses. Seedlings are raised at close spacing in lines, thinned, fertilised, earthed up and irrigated lightly; the haulms are cut after about 90–100 days. The resulting seedling tubers (commonly about 5–40 g) are harvested, graded and cold-stored, and are planted in the next season as seed tubers. Alternatively, seedlings raised in trays are transplanted to the field to produce a ware or seed crop. Because most potato viruses are not transmitted through true seed, this produces healthy seed at low cost and saves the 2–2.5 t/ha of tubers otherwise used as seed. This method, often supported by collaborations between institutions like CIP and CPRI, offers a significant advantage over conventional vegetative propagation by eliminating the accumulation of viral loads, thereby ensuring higher yields and better quality potatoes for farmers.

(c) Insect and Mite Pests of Brinjal Brinjal (Solanum melongena) faces pressure from various insect and mite pests. The Shoot and Fruit Borer (Leucinodes orbonalis) belongs to the class Insecta, order Lepidoptera, family Crambidae (earlier placed in Pyralidae). Larvae bore into tender shoots, which wilt and droop, and later into fruits, which show bore holes plugged with excreta and become unmarketable. The leafhopper (jassid) Amrasca biguttula (Hemiptera: Cicadellidae) sucks sap and causes 'hopper burn', leaf curling and yellowing. The hadda (epilachna) beetle Henosepilachna vigintioctopunctata (Coleoptera: Coccinellidae) scrapes leaves into skeletons. The Whitefly (Bemisia tabaci), classified under Insecta, Hemiptera, and Aleyrodidae, feeds on sap and acts as a vector for various plant viruses, reducing plant vigor. The red spider mite (Tetranychus urticae), belonging to Arachnida, Acari, and Tetranychidae, suck cell contents, causing stippling and leaf yellowing. Management strategies employ an Integrated Pest Management (IPM) approach. This includes weekly clipping and destruction of infested shoots and fruits, sex pheromone traps (about 100 per ha) for monitoring and mass trapping of the borer, release of egg parasitoids such as Trichogramma, need-based sprays of selective insecticides (e.g., emamectin benzoate or chlorantraniliprole for the borer, and neem products for sucking pests), and acaricides (e.g., spiromesifen) or wettable sulphur for mites. Bt brinjal resistant to the borer has been under a moratorium in India since 2010, though it is grown in Bangladesh. A balanced IPM strategy ensures sustainable control without excessive chemical reliance.

(d) Hunger and Malnutrition in India India continues to grapple with a complex nutritional landscape. According to NFHS-5 (2019–21), 35.5% of children under five are stunted, 19.3% wasted and 32.1% underweight, while 67.1% of children aged 6–59 months and 57% of women are anaemic. India was ranked 105th of 127 countries in the Global Hunger Index 2024 (a 'serious' level), though the government disputes the index's methodology. Simultaneously, there is a rising trend in obesity and lifestyle disorders, creating a "double burden" of malnutrition. To mitigate these issues, the government has launched several initiatives. POSHAN Abhiyaan (Prime Minister’s Overarching Scheme for Holistic Nourishment) focuses on convergent actions across sectors to reduce stunting and anemia. Under the National Food Security Act 2013, about 81 crore people receive subsidised grain, made free under the Pradhan Mantri Garib Kalyan Anna Yojana (PMGKAY) since January 2023 and extended for five years from 2024. PM POSHAN (the mid-day meal scheme) feeds schoolchildren, Mission Saksham Anganwadi and Poshan 2.0 cover children and mothers, and Anaemia Mukt Bharat targets anaemia. The Annapurna scheme supports the elderly, while fortified rice now supplied through PDS, ICDS and PM POSHAN, millet promotion and the Poshan Tracker app aim to improve dietary quality and monitoring. These measures collectively address both availability and accessibility of nutritious food, aiming to improve the overall health outcomes of the population.

(e) Technology in Public Distribution System (PDS) Technology is revolutionizing the efficiency and transparency of the Public Distribution System (PDS). The introduction of e-POS devices with biometric authentication ensures that only eligible beneficiaries receive their allotted rations, reducing leakage and ghost beneficiaries. Aadhaar seeding links beneficiary identities to unique IDs, preventing duplication and fraud. The One Nation One Ration Card (ONORC) initiative allows portability, enabling migrants to access rations at any Fair Price Shop across India. GPS-enabled vehicles track the movement of food grains from warehouses to shops, ensuring timely delivery and minimizing pilferage. The Integrated Management of PDS (IM-PDS) and the Annavitran portal give a national view of transactions, the Mera Ration app lets beneficiaries check entitlements and nearby shops, supply-chain software plans grain movement from FCI depots, and pilots such as the Annapurti grain ATM (Odisha, 2024) dispense grain automatically. These technological interventions streamline operations, reduce administrative costs, and ensure that food security benefits reach the intended poor and vulnerable sections of society more effectively.