低钾胁迫对西洋参某些生理特性的影响

为明确钾对西洋参幼苗生理特性的影响,运用水培试验技术,在霍格兰营养液基础上,设置4个钾浓度梯度为处理,分别为0,0.6,2.0,6.0 mmol/L,探索钾胁迫对西洋参幼苗叶片光合特性、碳氮代谢以及活性氧代谢的影响。结果表明:叶绿素a、叶绿素b和叶绿素总量均随着钾浓度的增加呈现先增加后降低的变化趋势,并在2.0 mmol/L的浓度下达到峰值,分别为12.88,6.96,19.84 mg/g。根系活力随着钾浓度的增加而逐渐增加,高钾浓度处理组比缺钾处理组西洋参根系活力高36.91%。缺钾显著降低了西洋参幼苗叶片的可溶性糖和可溶性蛋白含量。随着钾浓度的降低西洋参幼苗叶片MDA含量逐渐升高,SOD、POD和CAT等保护酶类的活性逐渐增强。低浓度的钾导致西洋参幼苗光合作用、根系活力和碳氮代谢等生理指标的下降以及膜脂过氧化作用的增强,从而抑制了西洋参幼苗的健康生长。

Effects of Low Potassium Stress on Some Physiological Characters of Panax quinquefolius

In order to investigate the effects of potassium on the physiological characters of Panax quinquefolius, on the basis of Hoagland nutrient solution, 4 treatments with different potassium con-centration (0, 0. 6, 2. 0 and 6. 0 mmol/L) were used to explore the changes of photosynthetic char-acteristics , carbon and nitrogen metabolism and active oxygen metabolism of Panax quinquefolius un-der potassium stress. Results indicated that chlorophyll a, chlorophyllb and total chlorophyll content increased initially and then decreased when potassium concentration increased and reached a peak at 2 mmol/L concentration, 12. 88,6. 96 and 19. 84 mg/g, respectively. When potassium concentration was increased, root activity increased. Root activity of Panax quinquefolius seedlings in high potassi-um group was 36. 91% higher than potassium deficient group. Potassium deficiencies significantly decreased content of soluble protein and soluble sugar. MDA and protective enzyme activities in-creased when potassium concentration declined. So the low potassium treatment decreased leaf physi-ological metabolism and restrained the growth of Panax quinquefolius seedlings.