(a) Describe the process of anaerobic respiration and explain the factors affecting respiration. (20 marks) (b) Discuss banana…

(a) Anaerobic Respiration and Factors Influencing Respiration

Anaerobic respiration begins in the cytoplasm with glycolysis, breaking glucose into pyruvate to yield a net of 2 ATP and 2 NADH, compared to 36–38 ATP (about 30–32 by current estimates) generated under aerobic respiration. In plant tissues deprived of oxygen (for example, waterlogged roots), lactic fermentation starts first, and the fall in cytoplasmic pH then switches the cell to alcoholic fermentation. In the absence of oxygen, pyruvate is reduced via fermentation pathways: alcoholic fermentation produces ethanol and CO₂ (catalysed by pyruvate decarboxylase and alcohol dehydrogenase), whereas lactic acid fermentation yields lactate (via lactate dehydrogenase) to regenerate NAD⁺.

Respiration rates are governed by temperature (operating under a Q₁₀ temperature coefficient of 2.0 to 2.5 within physiological limits), moisture availability, oxygen concentration (Pasteur effect and critical extinction point), respiratory substrate type (glucose versus lipids or organic acids), mechanical injury or bruising which induces wound respiration, and hormonal regulation such as ethylene-mediated climacteric surges. Anaerobic fermentation is harnessed in silage making, and controlled-atmosphere fruit storage lowers O₂ to slow respiration while keeping it above the anaerobic threshold, whereas poor soil aeration and waterlogging trigger root hypoxia, severely impeding nutrient uptake and crop vigour.

(b) Banana: Varieties, Nutrition, Protection and Post-harvest Handling

India cultivates diverse commercial cultivars: Grand Naine (the most widely planted tissue-culture Cavendish), Dwarf Cavendish and Robusta (high-yielding table varieties), Poovan (hardy and widely adapted), Nendran (Kerala’s primary processing and culinary variety), Red Banana, and the GI-tagged Hill Banana (Virupakshi).

Plants are commonly spaced at about 1.8 × 1.8 m. Nutrient management for Cavendish types commonly applies about 200 g N, 60–100 g P₂O₅ and 200–300 g K₂O per plant (banana has a very high potassium requirement), delivered through split schedules or drip fertigation, alongside foliar sprays to correct Zn, Fe, and Mn deficiencies. Integrated pest and disease management addresses Panama wilt (Fusarium oxysporum f. sp. cubense, race 1 and now the Tropical Race 4 strain reported from Bihar and Uttar Pradesh) via disease-free tissue-culture plants, resistant cultivars, crop rotation, soil solarization and biocontrol (Trichoderma), Sigatoka leaf spot through systemic fungicides, Banana Bunchy Top Virus by controlling the aphid vector (Pentalonia nigronervosa), and burrowing nematodes (Radopholus similis) through corm paring and nematicides. Post-harvest handling involves harvesting at about 75–80% maturity, dehanding, washing to remove latex, fungicide dip against crown rot, precooling, cold chain storage at 13–14°C (below about 12°C the fruit suffers chilling injury), and ripening in ethylene chambers (about 100 ppm for 24 hours at 18–20°C and 90–95% RH) to ensure uniform ripening.

(c) Food and Nutritional Insecurity Drivers

Despite bumper harvests and record buffer stocks, food insecurity persists due to purchasing power deficits and unequal physical access. The calorie-versus-nutritional security gap remains wide, as diets lack diversification, driving widespread micronutrient malnutrition. High post-harvest supply chain losses, climate-induced crop shocks, and pronounced regional disparities in eastern and tribal belts further compound insecurity. Policy bottlenecks include National Food Security Act (NFSA) targeting errors, Public Distribution System (PDS) leakages, buffer stock rot, and ad-hoc export-import restrictions. A sustainable way forward requires converging NFSA entitlements with POSHAN Abhiyaan, expanding millets and pulses in public procurement, and modernizing storage infrastructure to ensure holistic nutritional resilience.