玉米叶肉细胞和维管束鞘细胞中光合产物的分析

玉米苗照光后,叶肉细胞和维管束鞘细胞大量积累淀粉和可溶性糖(包括蔗糖),其中淀粉95％以上在维管束鞘细胞中。阻断光合产物输出时,两类细胞中蔗糖和淀粉积累都显著增加。离体维管束鞘细胞也能合成蔗糖。离体玉米叶内原生质体饲喂NaH~(14)CO_3并照光后,通常90％以上的~(14)C参入到有机酸和氨基酸中,3～10％参入糖和淀粉中。玉米叶肉原生质体具有直接利用CO_2合成碳水化合物的能力。

ANALYSIS OF PHOTOSYNTHETIC PRODUCTS IN MESOPHYLI CELLS AND BUNDLE SHEATH CELLS OF ZEA MAYS LEAVES

When 1 to 2 month old plants of Zea mays were illuminated for 8 hours, bothmesophyll cells and bundle sheath cells of the fully expanded leaves can accumulate-a large amount of soluble sugars, including sucrose. Both types of cells also ac-cumulate starch,of which 95% is in bundle sheath cells. The content of sucroseand starch in both mesophyll cells and bundle sheath cells increased markedlyto more than double the original amount when the export of photosynthetic pro-ducts was blocked. In isolated mesophyll protoplasts from maize leaves fed with NaH~(14)CO_3 andilluminated for 1 hour, usually more than 90% of ~(14)C was incorporated into organicacids and amino acids. About 3 to 10% of the ~(14)C incorporated was in sugarsand starch. This indicates that mesophyll protoplasts of maize leaves can producecarbohydrates from CO_2. Isolated bundle sheath strands can also produce sucrosefrom CO_2.