仙客来夏季休眠期叶片光合速率和植株氮磷钾质量分数的变化

仙客来Cyclamen persicum在夏季高温强光的休眠期间蒸腾速率上升,造成水分代谢失调,气孔阻力上升,光照强度和温度上升,光合速率下降.同时整个植株的全氮质量分数缓慢增加,全磷质量分数逐渐下降,全钾质量分数先增加后下降,源叶和根系中氮磷钾质量分数基本呈下降趋势,而球茎中的氮和钾有所积累,磷质量分数基本不变.这些变化趋势与仙客来遇高温强光停止生长而进入休眠的表现相一致.表4参17

Photosynthetic characteristics and N, P, K contents ofCyclamen persicum during the summer dormancy stage

During the dormancy stage with high temperature and strong light in summer, the transpiration rate of Cyclamen persicum increased, which led to moisture decompensation, rise in stoma resistance, rise in illumination intensity and temperature, and fall in photosynthesis rate. At the same time, the mass fraction of nitrogen increased slowly, that of phosphor decreased gradually, that of potassium first increased then decreased in the plant. The mass fractions of nitrogen, phosphor and potassium in the source leaves and roots decreased; while in the corm, those of nitrogen and phosphor accumulated and that of phosphor unchanged. These changes were consistent with the behaviors of Cyclamen persicum in the dormancy caused by high temperature and strong light.Ch,4 tab.17 ref.]