摘要
用含0（对照），50，100，150，200mmol／L浓度的NaCl的Hoagland营养液处理短穗柽柳（Tamarix lazaWilld．）扦插苗。结果表明：根际NaCl浓度从50mmd／L上升到200mmol／L时，根系对Na^＋的排斥量从占理论吸收值的87％上升到93％。随着根际NaCl浓度的上升，体内盐分通过盐腺分泌的绝对量始终是增加的。在根际NaCl浓度为50mmol／L时，植株的泌盐效率最高，随着根际NaCl浓度继续增加，相对分泌能力反而下降。白天吸收到植物体内的Na^＋有48％～53％在当天就被盐腺分泌出去。Na^＋总累积量随着根际NaCl浓度增加而增加，总累积与总吸收的比值在0．47～0．52之间。说明，根系拒盐是柽柳最重要的抗盐机制，而盐腺分泌的Na^＋量相对于柽柳植株地上部积累的Na^＋量而言可以达到50％。即，泌盐作用对柽柳地上部抗盐能力提供重要贡献。
Tarnarix laxa seedlings were treated by NaCl with different concentrations （0, 50, 100, 150 and 200 mmol· L^-1） to study the contribution of different processes of salt secretion, rejection and accumulation to the salt resistance capability of Tamarix laxa in saline environment, and the salt concentration and excretion in plant and salt dynamics in rhizosphere were determined. The results are as follows： （1） With an increase of NaCl concentration, the excretion of Na^＋ was increased from 87 % to 93 % of the theoretic capacity of absorption, additionally, the absolute salt secretion by salt gland was increased at the similar trend. （2） When the NaCl concentration was 50 mmol· L^-1, the secretion efficiency （the ratio of the secreted salt and the Na^＋ content in shoot） was increased to the maximum, but the relative secretion capacity was decreased. The salt absorbed at the daytime was secreted out by 53% -48% on the same day. The total accumulation of salt in shoot was increased with increasing the NaCl concentration in cultivation solution, the ratio of the total accumulation and the total absorption varied in a range from 0.47 to 0.52. In general, salt rejection from root plays the main role in salt resistance; although the Na^＋ secreted from salt gland takes a low proportion of the theoretic capacity of absorption compared to the Na^＋ accumulated by plant shoot, it possessed 50%, that means salt secretion has a high contribution to the salt resistance of Tamarix laxa Willd.
出处
《干旱区研究》
CSCD
北大核心
2007年第2期207-212,共6页
Arid Zone Research
基金
教育部科学技术研究重点项目(105012)
国家自然科学基金项目(30470341)资助
作者简介
丁效东（1978-），男，山东寿光人，硕士，从事植物营养生态和植物抗盐性研究．E-mail：xiaodongding2004@163．com
通讯作者：冯固．fenggu@cau．edu．cn
