(a) What is topiary ? Describe the characteristics of plants ideal for it. (10 marks) (b) Describe terrace garden and moon…

(a) Topiary and ideal plants for it (10 marks)

Topiary is the horticultural art of clipping, pruning and training live shrubs or trees, usually evergreen, into ornamental geometric shapes (cones, spheres, spirals) or figures such as animals and birds, often over a wire frame. It needs repeated shearing through the year.

Characteristics of plants ideal for topiary:

• Small, dense, evergreen foliage with a fine texture, so the shape looks smooth.
• Compact, slow to moderate growth, which keeps the shape between clippings.
• Profuse branching with short internodes, and the ability to bud from old wood, so bare patches fill.
• Tolerance to repeated close clipping and quick recovery after it.
• Hardiness to local heat, drought and pests, and a long life.
• A flexible stem, for training on frames.

Examples: boxwood (Buxus), Duranta, Murraya paniculata, Ficus benjamina, Thuja, Juniperus, cypress and Pyracantha. Clipping is done on a regular schedule, and fertilising and watering keep the foliage healthy.

(b) Terrace garden and moon garden (10 marks)

A terrace (roof) garden is a garden made on the roof or terrace of a building, in containers, raised beds or a layered green-roof system. It needs a structural check of the roof load, waterproofing and a root barrier, a drainage layer, and a light growing medium (soil with cocopeat, compost, perlite or vermiculite). Drip irrigation, wind protection, shade and shallow-rooted, drought-tolerant plants (flowers, herbs, vegetables, small shrubs) are used. It lowers the building temperature, saves energy, reduces run-off, and gives food, space for recreation and cleaner air, in crowded cities.

A moon garden is a garden designed to be enjoyed at night, in moonlight and in the evening. It uses white or pale flowers and silver or grey foliage, which reflect the light, and night-blooming, strongly scented plants, such as raat ki rani (Cestrum nocturnum), night jasmine (Nyctanthes), tuberose, mogra, moonflower (Ipomoea alba) and four o'clock. Light paths, a pool that mirrors the moon, seating and soft lighting complete it.

(c) Quality indices for cauliflower, cabbage and broccoli (10 marks)

Quality is judged by the appearance, freshness and edibility of the part sold.

• Cauliflower (the curd): a compact, firm, smooth, creamy-white curd of uniform size, protected by trimmed wrapper leaves, and free of riceyness, fuzziness, leafiness, buttoning, browning or discoloration, and of insect and disease damage. A curd that is too mature is loose.
• Cabbage (the head): a firm, solid, compact head of the right size, weight and shape for the variety, with a small core, a fresh, clean colour, and no splitting, tipburn, or insect or disease damage.
• Broccoli (the head): a tight, compact, dark green (or purple) head with small, uniform, tightly closed buds, a firm and tender stem, and no yellowing, open flowers or bracts, which show age and delayed harvest.

Shared indices: freshness (turgor, no wilting), uniformity, freedom from pesticide residue, and, for nutrition, vitamin C, dry matter and glucosinolates. The shelf life depends on cooling soon after harvest.

(d) Major constraints for enhancing food grain production in India (10 marks)

• Shrinking and fragmented landholdings, which raise costs and block mechanisation.
• Degradation of soil: declining organic carbon, imbalanced use of nitrogen, phosphorus and potassium, micronutrient deficiencies, salinity and waterlogging.
• Water scarcity: falling groundwater levels in intensive areas, and dependence on the monsoon where irrigation is missing.
• Climate variability: erratic rainfall, drought, floods and heat stress, especially in the wheat grain-filling period.
• Yield plateau of the Green Revolution varieties in the main cereal areas, and slow spread of new varieties and technology on marginal lands.
• Pests, diseases and weeds, and poor availability of quality seed.
• Post-harvest losses in storage and handling, and weak market and price support outside some crops and regions.
• Inadequate credit, extension and investment, and a shift of area to more profitable crops.

Remedies include efficient irrigation, integrated nutrient management, climate-resilient varieties, farm mechanisation and better extension.

(e) Role of osmoprotectants under salt and water stress (10 marks)

Osmoprotectants (compatible solutes or osmolytes) are small, highly soluble, non-toxic organic molecules that accumulate in cells under salinity and water deficit without disturbing metabolism. Examples: proline, glycine betaine, trehalose, mannitol, sorbitol, sucrose and polyamines.

Roles:

• Osmotic adjustment: they lower the osmotic potential of the cytoplasm, so cells keep turgor and take up water, while toxic Na⁺ is sequestered in the vacuole.
• Protection of proteins, enzymes and membranes, including photosystem II, from denaturation, acting as chemical chaperones.
• Scavenging of reactive oxygen species, reducing oxidative damage.
• Storage of carbon and nitrogen, and a source of energy on recovery.

Plants may be given better tolerance by exogenous application, or by transgenes for their synthesis (betA, P5CS, otsA and otsB, mtlD).