苗木蒸腾和Na+吸收对切根及NaCl处理的响应

盐碱地造林时根系伤口对盐分吸收有无影响至今未见报道.本研究在150 mmol NaCl处理的水培条件下,切断供试苗木的吸收根,通过检测叶被害率、蒸腾速率及苗木根、枝干和叶中Na 含量,进一步阐明蒸腾和Na 吸收对切根及NaCl处理的响应.试验结果表明:(1)青栲和金木犀两树种的切根处理都使Na 含量和含有率增大,导致叶被害率升高;(2)与对照及不切根做NaCl处理及切根后3 d做NaCl处理相比,切根后立即进行NaCl处理的苗木,Na 的吸收显著增多,苗木盐害最重,蒸腾速率降低的幅度也最大;切根后放置3 d,Na 吸收和盐害明显受到抑制;(3)随着蒸腾速率的增大,青栲和金木樨的Na 吸收量都增加,且金木樨的二者的相关关系呈极显著(r= 0.613**,n=18).这为盐碱地造林措施的改进提供了理论依据,即在盐碱地造林时最好采用不需要修剪根系的苗木,如果确有修剪的必要,也要在修剪并经过几天圃地的假植后再行种植,避免盐分被迅速吸收,使苗木遭受盐害.

Response of Transpira tion and Na+ Intake of Seedlingto Cutting Root and NaCl Trea tments

There were no report on whether cutting root influence salinity intake in afforestation in saline-alkali soils.To further examine the response of transp iration and Na⁺ intake of seedling to cutting root and NaCl treatment, itwastested to leaf damage rate, transp iration rate and Na⁺ content in the root, branches and leaves, by cutting absorption root of the seedling of Cyclobalanopsis m y rsinaefolia and Osm anthus fragrans var. auran tiacus under the condition of 150 mmol NaCl treatment. The results showed: (1) Cutting root treatments of both C. m yrsinaefolia and O.fragrans var. auran tiacus resulted in the increase ofNa⁺ content and its content ratio, which leaded to the increasement of leaf damage rate. (2) If NaCl treatmentswere immediately done after cutting root, itwas significant to increase Na⁺ up take, caused serious salinity p roblems, and largest range of decrease of transp iration rate. In contrast,if NaCl treatmentswere done on 3 days after cutting root, Na⁺ intake and salinity p roblems were obviously inhibi2ted. (3) Na⁺ up take increased with the increase of transp iration rate in C. m y rsinaefolia and O. frag rans, and therewas a significant positive correlation ( r = 0. 613^**, n = 18) between Na⁺ up take and transp iration rate for O. fragrans. All these suggested that it was not feasible for afforestation in saline2alkali soils to cutting root of seedling,however, if itmust be cut, it was necessary to heeling-in for a few days in the garden to p revent salinity p roblem from the rap id up take of salinity.