遮光对3种地被植物生长和生理生化的影响

Shading with growth, physiological indexes,biochemical indexes of three ground-cover plants

对花叶玉簪甜心Hosta×hybrida‘So Sweet’,花叶蜘蛛抱蛋Aspidistra elatior‘Punctata’和白穗花Speirantha gar-denii等3种地被植物进行不同程度遮光处理,研究了遮光条件下3种植物形态指标、叶片叶绿素质量分数、丙二醛(MDA)质量摩尔浓度和保护酶活性的变化。结果表明:在遮光处理下,3种植物形态指标都显著高于对照(全光照),花叶玉簪甜心在遮光75%下达到最大值,花叶蜘蛛抱蛋和白穗花在遮光90%下达到最大值。3种植物叶片叶绿素a、叶绿素b质量分数均较对照显著升高,以白穗花的增幅最大。叶绿素a/b比值显著下降,以白穗花的降幅最大。3种植物丙二醛质量摩尔浓度变化呈先下降后上升的趋势,但均显著低于对照;3种植物的超氧化物歧化酶(SOD)活性均显著低于对照,花叶玉簪甜心叶片的SOD活性先下降后上升,花叶蜘蛛抱蛋和白穗花叶片的SOD活性呈缓慢下降的趋势;花叶玉簪甜心和花叶蜘蛛抱蛋过氧化物酶(POD)活性变化均为先下降后上升,白穗花叶片的POD活性在遮光50%时下降,而到遮光75%时又明显上升,后又下降。通过隶属函数法综合分析可知,3种地被植物的耐荫性由强到弱为:白穗花>花叶蜘蛛抱蛋>花叶玉簪甜心。

Changes in morphological indexes, chlorophyll mass fraction, malondialdehydel （MDA） molal concentration and protective enzyme activities of Hosta x hybrida ‘So Sweet＇, Aspidistra elatior ‘Punctata＇, Speirantha gardenii with shading treatments of 50%, 75%, 90% and a control of 0% were studied using the subordination function method. Results showed that the morphological indexes of the three plants were 75% significantly higher （P〈0.05） than the control. Indexes of H. x hybrida ‘So Sweet＇ were shading , but the indexes of A. elatior ‘Punctata＇ and S. gardenii were largest with 90% greatest with shading. The mass fraction of chlorphyll a （Chl a） and chlorphyll b （Chl b） for shading treatments were significantly higher（P〈0.05） than the control and the increased range of S. gardenii was biggest. Chl a/Chl b was significantly lower （P〈0.05） than the control and the decreased range of S. gardenii was biggest. Malondialdehyde （MDA） molal concentration was significantly lower （P〈0.05） with shading treatments than the control. The changes of superoxide dismutase （SOD） activities of H. x hybrida ‘So Sweet＇ decreased first and then increased, while those of A. elatior ‘Punctata＇ and S. gardenii gradually decreased. With increased shading, changes in peroxidase（POD） activities of H. x hybrida ‘So Sweet＇ and A. elatior ‘Punetata＇ decreased to a certain degree and then increased. POD activities of S. gardenii decreased with 50% shading,but increased with 75% shading and then decreased. According to the subordination function method, shade tolerance of the three plants was in the order： Speirantha gardenii〉Aspidistra elatior ‘Punctata＇〉Hosta × hybrida ‘So Sweet＇. [Ch, 3 fig. 3 tab. 22 ref.]