C4gräsarter

C4gräsarter refers to a group of plant species belonging to the family Poaceae, commonly known as grasses, that utilize a specific photosynthetic pathway called the C4 pathway. This pathway is an adaptation to hot, dry, and sunny environments. Unlike the more common C3 photosynthesis, C4 photosynthesis has a preliminary step that concentrates carbon dioxide around the enzyme RuBisCO, which is the primary enzyme involved in carbon fixation. This mechanism reduces photorespiration, a process that occurs in C3 plants and reduces photosynthetic efficiency, especially under high temperatures and light intensities.

The C4 pathway involves a spatial separation of initial carbon fixation and the Calvin cycle. Carbon dioxide is first fixed in mesophyll cells into a four-carbon compound, typically oxaloacetate, which is then converted to malate or aspartate. These four-carbon acids are transported to bundle sheath cells, which surround the vascular bundles in the leaves. Within the bundle sheath cells, the four-carbon acids are decarboxylated, releasing carbon dioxide. This concentrated CO2 is then refixed by RuBisCO and enters the Calvin cycle, similar to C3 photosynthesis. This biochemical and anatomical adaptation allows C4 plants to maintain high rates of photosynthesis and productivity even under stressful conditions.

Examples of economically important C4 grass species include maize (Zea mays), sugarcane (Saccharum officinarum), sorghum (Sorghum bicolor), and many warm-season turfgrasses and forage grasses. These plants are crucial for global food security, animal agriculture, and landscape management due to their efficient resource utilization and high biomass production in suitable climates.