| 摘要: |
| 【目的】明确巫山红叶秋季叶片呈色不均的主要影响因子。【方法】在巫山红叶景区内，根据海拔、坡度、坡向的不同选取4种具有代表性的生境（生境1，生境2，生境3，生境4），并以其中生长的巫山红叶（Cotinus coggygria Scop. var.cinerea Engl.）为试验材料，于2018年7-11月，在每月20日采样并立即测定叶片叶绿素、类胡萝卜素、花色素苷、可溶性蛋白、还原性糖含量以及苯丙氨酸解氨酶（PAL）活性,通过分析叶片生理指标的变化及其与环境因子（海拔、坡向、坡度、土壤营养状况以及环境温度、湿度）的相关性，明确引起红叶呈色差异的主要因子。【结果】各生境巫山红叶叶片中叶绿素和类胡萝卜素含量随生长期不同存在差异，在11月时急速下降，与10月相比，叶绿素含量降幅为80.42%～92.86%，类胡萝卜素含量降幅为55.58%～86.22%；生境3、生境4中的叶绿素与类胡萝卜素含量始终低于生境2，且在11月转色期时显著低于生境2（P＜0.05）。各生境巫山红叶叶片中花色素苷含量在转色期前整体较低，在11月转色期时急剧上升，其中海拔最高、坡度最陡的生境4中其含量相比10月上升了10.04倍，并显著高于其他生境（P＜0.05）。各生境巫山红叶叶片中PAL活性变化幅度与花色素苷含量变化情况并不一致，两者之间无显著相关关系，且转色期时不同生境之间PAL活性也无显著差异。各生境巫山红叶叶片中可溶性蛋白含量在11月转色期时大幅下降，生境4较之10月下降了83.64%，降至最低，但与其他生理指标间无显著相关性。转色期时，巫山红叶叶片中还原性糖含量与花色素苷含量呈显著正相关（P＜0.05），其中生境4的还原性糖含量最高，但与其他生境的还原性糖含量无显著差异（P＞0.05）。相关性分析结果表明，花色素苷和还原性糖含量与海拔、坡度呈显著正相关关系（P＜0.05），与温度、湿度呈显著负相关关系（P＜0.05），而与坡向和土壤肥力条件无显著相关性（P＞0.05）。【结论】海拔与坡度、温度与湿度是导致不同生境内巫山红叶转色期叶片呈色不均的关键外在因素；还原性糖由于在一定含量范围内会影响花色素苷含量的变化，是导致叶片呈色不均的一个重要内因。 |
| 关键词: 巫山红叶 生境 叶色 生理因子 |
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| 基金项目:重庆市硕士研究生科研创新项目(CYS19123)；中央高校基本科研业务费项目（XDJK2019D041）；国家级大学生创新创业计划项目（201810635015） |
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| Response of Cotinus coggygria to habitat heterogeneity in Wushan |
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ZHANG Wen,WU Jiaojiao,GAO Lan,et al
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| Abstract: |
| 【Objective】The main purpose of this study was to identify main factors affecting color unevenness of C. coggygria Scop. var. cinerea Engl. leaves during autumn in Wushan.【Method】In Wushan red leaf scenic area,four representative habitats (habitat 1,habitat 2,habitat 3 and habitat 4) were selected according to altitude,slope and aspect.From July to November 2018 samples of red leaves were taken on the 20th of each month and contents of chlorophyll,carotenoid,anthocyanin,soluble protein and reducing sugar and activity of phenylalanine ammonia lyase (PAL) were determined.By analyzing the changes of physiological indexes of leaves and their correlation with environmental factors (altitude,slope direction,slope,soil nutrient status,ambient temperature and humidity),the main factors causing color difference were identified.【Result】The contents of chlorophyll and carotenoids varied with the growth period,and decreased rapidly in November.Compared with October,chlorophyll content decreased by 80.42%-92.86%,and carotenoid content decreased by 55.58%-86.22%.The contents of chlorophyll and carotenoids in habitat 3 and habitat 4 were always lower than that of habitat 2,and they were significantly lower than that of habitat 2 in the color changing period in November (P<0.05).The anthocyanin content was low before the color changing period,and increased sharply during the color changing period in November.The anthocyanin content of habitat 4 with the highest elevation and steepest slope increased by 10.04 times compared with that of October and was significantly higher than that in other habitats (P<0.05).The change of PAL activity was not consistent with that of anthocyanin content without significant correlation between them,and there was no significant difference in PAL activity among different habitats during the color changing period.The soluble protein content decreased sharply during the color changing period in November,and plants in habitat 4 decreased by 83.64% to the lowest level compared with that in October,but there was no significant correlation with other physiological indicators.The reducing sugar content was positively correlated with anthocyanin content (P<0.05),and the reducing sugar content of habitat 4 was the highest,but there was no significant difference among other habitats (P>0.05).Correlation analysis showed that anthocyanin and reducing sugar contents were significantly and positively correlated with elevation and slope (P<0.05),and they had significant negative correlation with temperature and humidity (P<0.05) rather than slope direction and soil fertility (P＞0.05).【Conclusion】Elevation and slope were the key external factors leading to uneven coloration of red leaves during the color changing period in different habitats,and reducing sugar was an important internal cause due to its influence on variation of anthocyanin content. |
| Key words: red leaves of Wushan habitat leaf color physiological factors |
