Cactus Survival Adaptations: PTE Listening: Fill in the Blanks practice questions

Desert cacti possess distinctive internal structures that allow them to endure long periods without rain. The outer skin is coated in a thick layer that prevents moisture from escaping into the dry air. Beneath the surface, the plant tissue functions like a sponge, expanding rapidly to store liquid after brief downpours. Rather than relying on traditional foliage, these plants have transformed their leaves into sharp that provide protection from thirsty herbivores. This physical structure also creates miniature areas of that reduce temperature stress. Consequently, the stem carries out all the essential processes needed for growth while keeping overall fluid loss remarkably low.

To survive extreme heat, many desert plants have evolved a specialised metabolic rhythm known as crassulacean acid metabolism. Unlike standard flora that open their pores during daylight, cacti keep their microscopic tightly closed while the sun is bright. They only take in carbon dioxide during the cooler night hours, storing it chemically until dawn. When sunlight returns, the plant breaks down these compounds to produce vital sugars without exposing internal to the parched atmosphere. This delayed sequence represents an exceptionally strategy, allowing the cactus to maintain essential functions while conserving almost all of its stored water.

Underneath the dry desert ground, cacti develop a subterranean architecture that differs greatly from deep taproots. Their root systems spread out horizontally across an impressive , remaining just below the surface. This shallow network ensures that whenever light rain falls, the plant can capture moisture before it can in the intense heat. Furthermore, some desert species produce temporary hair roots within hours of precipitation, which drastically increase the surface area available for uptake. Once the soil dries out again, these fragile filaments naturally to prevent precious fluid from flowing back into the surrounding earth.