缺硼对绿豆叶片光合特性和碳水化合物含量的影响

本试验以绿豆为指示植物，采用溶液培养法研究了缺硼对叶片光合功能和碳水化合物含量的影响，以明确缺硼是否影响光合作用进而影响作物生长。在绿豆第二片真叶出现后的第二天，一半植株供给 50 mol/L 硼（高硼），另一半植株供给0.2 mol/L 硼（低硼），在叶片生长过程中动态监测叶绿素含量、 气体交换和碳水化合物含量。结果表明，缺硼对叶片叶绿素含量没有影响，缺硼降低了光合速率（Pn）和气孔导度（Gs），但对胞间二氧化碳浓度（Ci）没有影响; 缺硼提高了气孔限制率（Ls）。虽缺硼降低了Pn，但提高了叶片中可溶性糖，特别是葡萄糖和淀粉的含量。本研究结果表明缺硼对植物生长的影响并非是由于碳水化合物缺乏的缘故，而是因降低库活力导致了Pn的降低。

Effects of boron deficiency on photosynthesis and carbohydrate contents in leaves of mung bean (Phaseolus aureus Roxb)

Effects of boron (B) deficiency on leaf functions of mung bean, photosynthesis and carbohydrate contents, were investigated to establish whether the inhibited growth of boron deficient plants was caused by diminished photosynthesis. Mung bean (Phaseolus aureus Roxb) seedlings were grown in solution culture at two B levels, 0.2 mol/L B (low level) and 50 mol/L B (high level) two days after the appearence of the second trifoliate leaf of mung bean. Changes in chlorophyll content, gas exchange and carbohydrate content were determined during the growth of the second trifoliate leaf. The results demonstrated that the boron deficiency has less effects on chlorophyll content and internal CO2 concentrations (Ci), decreased the CO2 assimilation and stomatal conductance (Gs). The calculated relative stomatal limitation (Ls) of boron deficient plants is enhanced. The boron deficiency increases soluble sugar, particularly glucose, and starch contents in contract to the reduce of photosynthetic rates. The results suggest that the inhibited growth of boron deficient plants is not brought about by shortage of carbohydrate, but the low photosynthetic rate due to the low sink activity.