大叶白蜡幼苗生长对不同光强遮荫处理的响应

Responses of Fraxinus rhynchophylla Seedlings to Shading Under Different Lilght Regimes

在不同光照梯度(55.44%自然全光照(natural sunlight,NS)、21.12%NS、3.47%NS和0.86%NS)的人工遮荫条件下,研究了大叶白蜡(Fraxinus rhynchophylla)幼苗的生长特点。结果表明,幼苗株高、基径、主根长、单株叶面积、总干重、相对生长率和净同化率等生长参数均在55.44%NS最大,分别为70.0 cm、6.84 mm、31.95 cm、798.80 cm2、10.28 g、31.13×10-3g.d-1和3.25×10-5g.cm-2.d-1,而且随光照的减弱而减小。幼苗比叶面积随着光照强度的减弱先增大后减小,在3.47%NS处理最大(597.43 cm2.g-1)。

Under different light regimes： 55. 44% natural sunlight （NS）, 21. 12% NS,3. 47% NS and 0. 860% NS in shade house, the growth characteristics of Fraxinus rhynchophylla seedlings were ob- served. The results showed that seedling height, basal shoot diameter, taproot length, leaf area per seedling, total dry weight, relative growth rate and net assimilation rate all maximized （70.0 cm, 6.84 ram, 31.95 cm, 798.80 cm2, 10.28 g, 31.13×10^-3g·d-1 , and 3.25×10^-3g·com-1·d-1 respectively） under 55.44% NS shade treatment and reduced with the decrease of light intensity. With the reduction of light intensity, the specific leaf area of F. rt2ynchoptyylla seedlings increased to its maximum （597.43 cm2·g-1） under the shade treatment of 3.47% NS, after which a decrease was observed.