土壤水分对乌桕秋叶生理指标及观赏效果的影响

Effects of Soil Water Content on Physiological Indexes and Ornamental Effects of Triadica sebifera Leaves in Autumn

以乌桕无性系盆栽苗为试验材料,采用盆栽控水法,通过设置4个水分胁迫处理,其土壤含水量分别为田间最大持水量的80%(对照组)、65%(轻度胁迫)、50%(中度胁迫)和35%(重度胁迫),探讨了土壤水分胁迫对乌桕秋叶生理指标及观赏效果的影响。结果表明:叶变色过程中,不同处理的叶绿素质量分数均逐渐减少,而花色素苷质量分数大幅升高,类胡萝卜素升高后下降。与此同时,可溶性糖质量分数呈上下波动变化,色度值L^(*)和b*值总体升高后下降,而a^(*)随叶色变红而变大,并与花色素苷呈极显著正相关(P<0.01)。中度和重度胁迫的叶绿素降解量和花色素苷合成量最多,均与对照有显著差异(P<0.05),但中度胁迫下的花色素苷积累更早,并且色度值L^(*)和a^(*)值均最高。在乌桕秋季叶色变化过程中,中度和重度胁迫都能在一定程度上使叶色变化时间提前,中度胁迫下观赏期更长,生长受影响有限且叶色更红艳亮丽,视觉观赏效果好。

We used potted seedlings of Triadica sebifera as the test materials, set up four water stress treatments, including the soil water content was 80%(control group), 65%(mild stress), 50%(moderate stress), and 35%(severe stress) of the field maximum moisture capacity respectively, to explore the effects of soil water content on the physiological indexes and ornamental effect of T. sebifera leaves in autumn. During the process of leaf discoloration, the chlorophyll content gradually decreased, while the anthocyanin content increased significantly, and the carotenoid content increased and then decreased under all treatments. The soluble sugar content fluctuated up and down, the values of L^(*) and b* generally increased and then decreased. The value of a^(*) increased when the leaf color turned red, which was extremely significantly positively correlated with anthocyanin content(P<0.01). The amount of chlorophyll degradation and anthocyanin synthesis were the most under moderate and severe stress, both significantly different from the control group(P<0.05). Under moderate stress, anthocyanin accumulation was earlier, and the values of L^(*) and a^(*) were both highest. In summary, moderate and severe stress could shorten the process of leaf color changing from green to red in autumn. However, the ornamental period will be longer, the growth will be less affected and the leaf color will be more red and bright under moderate stress treatment with better visual effect.