喜钙和嫌钙植物对外源Ca2+的生长生理响应

以喜钙植物伞花木和嫌钙植物大白杜鹃为实验材料,以Hoagland营养液并设置其Ca2+浓度分别为0、5、10、25、50mmol/L培养试验,比较不同浓度外源Ca2+对其生长、叶绿素含量、渗透调节和矿质元素积累的影响,探索喜钙植物生长的适应特征,为喀斯特地区喜钙植物嗜钙机制研究提供基础资料。结果显示:(1)随着外源Ca2+浓度的增加,伞花木植株高度、茎粗以及叶干重、叶长、叶宽和叶形指数均得到不同程度提高,叶绿素和可溶性蛋白质含量增加,脯氨酸和可溶性糖含量无显著变化;而嫌钙植物大白杜鹃的生长却受到抑制,叶绿素和蛋白质含量降低,脯氨酸和可溶性糖含量增加;当Ca2+浓度为50mmol/L时,伞花木叶绿素和蛋白质含量分别为2.99mg/g和17.10mg/g,大白杜鹃叶绿素和蛋白质含量分别为1.39mg/g和14.30mg/g。(2)在实验设置的钙范围内,Ca2+可促进伞花木对P、N吸收并稳定体内Ca、K动态;而低浓度的Ca2+(<10mmol/L)促进大白杜鹃对Ca累积,抑制N、P吸收。

Responses of Growth and Physiology of Calcicoles and Calcifuges to Exogenous Ca2+

The calcicole,Eurycorymbus cavaleriei,and calcifuge,Rhododendron decorum,were used as experimental materials to compare the responses of growth,chlorophyll content,osmoregulation and mineral element accumulation to different exogenous Ca²⁺ by addition 0,5,10,25 and 50 mmol/L Ca²⁺ in the Hoadland solution for culture medium.The results showed that:(1)Several parameters of E.cavaleriei such as plant height,leaf dry weight,leaf length,leaf width,leaf index,stem diameter,contents of chlorophyll and protein were promoted,and contents of proline and soluble sugar had no significant changes,with the increase of exogenous Ca²⁺ concentration.However,for R.decorum,these parameters appeared opposite trend and shown a restrained result.The contents of chlorophyll and protein decreased and the contents of proline and soluble sugar increased.The contents of chlorophyll and protein of E.cavaleriei were 2.99 mg/g and 17.10 mg/g,respectively,while the contents of chlorophyll and protein of R.decorum were 1.39 mg/g and 14.30 mg/g,respectively with 50 mmol/L Ca²⁺ in the Hoadland solution.(2)E.cavaleriei have Ca,K homeostasis and higher P,N absorption,while R.decorum is remarkable calcium accumulation and constraint of P,N absorption at lower calcium concentration.