光照强度对三个虎耳草观赏品种的形态及生理指标的影响

Effects of light intensities on morphological and physiological indexes of three ornamental cultivars of Saxifraga stolonifera

虎耳草(Saxifraga stolonifera)是一种观赏价值较高的阴生植物,常用于庭院绿化。光照强度对虎耳草的生长表现尤其是叶色、叶斑形成及其颜色深浅可能具有重要影响,从而影响其观赏价值。为探讨不同虎耳草品种对光强的适应能力及其最佳郁闭度,该研究以我国国际登录的三个虎耳草品种为材料,分析100%、85%、60%、40%和15%5种不同光照强度处理对植株生长发育和光合生理指标的影响,并通过主成分分析筛选虎耳草耐阴能力的适宜指标。结果表明:(1)随着遮荫度增加,叶片数、叶长、叶宽、叶面积、比叶面积、叶绿素a、叶绿素b和总叶绿素的含量呈上升趋势。(2)随着遮荫度增加,生成匍匐茎的条数、地上部分鲜重、地上部分干重、匍匐茎直径、类胡萝卜素和类黄酮的含量呈先上升后下降趋势。(3)随着遮荫度增加,叶片的最大荧光值、可溶性糖、可溶性蛋白和丙二醛的含量呈下降趋势。(4)主成分分析和隶属函数分析显示,三个虎耳草品种对不同光照的适应能力存在明显差异,即‘雪纹’>‘天目恩赐’>‘黑魁’,其中‘雪纹’的最适光照度为40%,‘天目恩赐’和‘黑魁’的最适光照度为15%~40%。在园艺实践推广应用中,对不同品种应选择在不同的适宜光照条件下栽培,该研究结果为合理利用虎耳草观赏品种提供了实践指导。

As a shade plant with high ornamental value,Saxifraga stolonifera is often used in landscape of courtyards and gardens.The light intensity may have an important infuence on its growth performance,especially on leaf color,formation and coloration of leaf variegation,which subsequently affects its ornamental value.However,the related study has not been reported before.In order to explore the adaptability of different cultivars of S.stolonifera to light intensity and understand their light or shade tolerance,three internationally-registered cultivars raised in China were used as the experimental materials,the effects of five light intensity treatments(100%,85%,60%,40%and 15%)on plant growth and development and photosynthetic physiological indexes were investigated.The suitable indexes of light intensity for S.stolonifera were screened by the principal component analysis,and the light tolerance of the cultivars was evaluated by membership function analysis.The results were as follows:(1)The number of blades,leaf length,leaf width,leaf area,specific leaf area,chlorophyll a,chlorophyll b and total chlorophyll contents increased with shading.(2)The number of stolons,fresh weight above ground,dry weight above ground,stolon diameter,and the contents of carotenoid and flavonoids increased first and then decreased.(3)The maximum fluorescence value and the contents of soluble sugar,soluble protein and malondialdehyde of the leaves decreased with shading.(4)By analysis of principal component and membership function,the significant differences were found in the adaptability of the three cultivars to light intensity,‘Xue Wen'>‘Tianmu Enci'>‘Hei Kui'.In which,40%light intensity was optimal for‘Xue Wen',and 15%-40%light intensities were optimal for‘Tianmu Enci'and‘Hei Kui'.Therefore,in horticultural practice,the suitable light intensity should be considered according to the cultivars of Saxifraga.