光照强度对大花旋蒴苣苔叶形态和生理指标的影响

Effects of light intensity on the leaf morphology and physiological parameters of Boea clarkeana

以复苏植物大花旋蒴苣苔(Boea clarkeana)为盆栽实验材料,通过梯度遮光处理,研究不同光照强度(100%、80%、60%、40%和20%透光率)和不同处理时间(30、60、90、120和150d)对大花旋蒴苣苔叶生长指标和生理指标的影响。结果表明:随着光照强度的减弱,大花旋蒴苣苔叶的各生长指标(叶片长、叶片宽、叶柄长、叶柄直径以及叶面积)呈现先增大后减小的趋势,透光率为60%时达到最大值;全光照(100%透光率)时,大花旋蒴苣苔表现出明显的外伤症状,透光率为80%和20%时,分别表现出中度伤害和轻度伤害,透光率为40%和60%时,未出现明显的外伤症状;过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)3种抗氧化酶活性均较低且随着光强减弱呈现先降低后升高的趋势,随着处理时间的延长呈先上升后下降的趋势,全光照时抗氧化酶的活性最大,透光率60%处理下酶活性相对较低;丙二醛(MDA)含量、脯氨酸(Pro)含量和质膜透性随着光强减弱呈先降低后升高的趋势,随着处理时间的延长显著升高;叶绿素含量随着光强减弱呈逐渐上升的趋势,随着处理时间的延长先降低后升高。分析表明,40%～60%的透光率有利于大花旋蒴苣苔的生长,强光和弱光对大花旋蒴苣苔的生长均不利。

A pot experiment was conducted to study the effects of light intensity （ 100%, 80%, 60%, 40%, and 20% of full light radiation） and exposure time （30, 60, 90, 120, and 150 days） on the leaf growth and physiological parameters of Boea clarkeana. With the decline of light intensity, the leaf morphological parameters （ blade length and width, petiole length and di- ameter, and leaf area） of B. clarkeana decreased after an initial increase, with the maximum at 60% of full light radiation. Conspicuous injury on B. clarkeana leaves appeared under full light radiation, moderate to slight injury developed under 80% and 20% of full light radiation, while un-conspicuous injury was observed when the light intensity was 40% and 60% of full light radi- ation. The activities of antioxidant enzymes （ CAT, SOD, and POD） were relatively low, and in- creased after an initial decrease with the decline of light intensity but showed a contrary trend with the increase of exposure time to light radiation. The activities of the antioxidant enzymes were the highest at full light radiation, and the lowest at 60% of full light radiation. The MDA content, proline content, and plasma membrane permeability increased after an initial decrease with the decline of light intensity, but increased significantly with the increase of exposure time. The chlorophyll content presented an increasing trend with the decline of light intensity, and in- creased after an initial decrease with the prolongation of exposure time. In sum, 40% -60% of full light radiation was beneficial, but weak and strong light radiations were adverse to B. clarkeana growth.