郑恬静+王克凤+桑瀚旭

摘要：以王族海棠（Malus ‘Royalty）和光辉海棠（Malus ‘Guanghui）秋季（8～10月）成熟叶片为试验材料，观察其叶色变化，并对其叶绿素、花色素苷、可溶性糖含量及苯丙氨酸解氨酶（PAL）活性进行测定，以期揭示两种海棠叶片色泽、内色素变化与其内源物质的相关关系。结果表明，王族海棠叶片虽生育期呈现紫红色，但秋季却出现“返绿”现象；光辉海棠则随着温度升高，叶片由绿色转变为红色，温度降低，红色退去，叶片呈现绿色。上述指标测定结果显示，两种海棠叶色表现均与叶片内色素的比例密切相关。王族海棠叶片内当花色素苷与叶绿素含量比值降至14时，其叶色由紫红色转变为绿色，其叶色变化主要是由花色素苷降解而叶绿素的积累引起的；光辉海棠成熟叶片的叶色变化则是由花色素苷和类胡萝卜素的含量共同决定的，花色素苷与叶绿素含量比值升至3、类胡萝卜素大量积累时，其叶色由绿色转变为橙红色。可溶性糖为花色素苷的合成提供原料和能源，PAL活性和叶片内色素的合成有必然联系，但不是惟一决定色素合成的调控酶。

关键词：海棠（Malus baccata）；叶色变化；花色素苷

中图分类号：S661.4 文献标识码：A 文章编号：0439-8114（2017）15-2908-05

DOI：10.14088/j.cnki.issn0439-8114.2017.15.028

Abstract： The autumn leaves of Malus ‘Royalty and Malus ‘Guanghui were used to study the changes of the leaf color， and the content of chlorophyⅡ， anthocyanin， soluble sugar and PAL activity were measured， in order to explore the relationship between the leaf color change of Malus and endogenous substances in autumn. The results showed that， the leaf color of Malus ‘Royalty rendered purple red in growth stages， but changed to green in autumn. The leaf color of Malus ‘Guanghui turned from green to red as the temperature rised， then changed to green when the temperature decreased. The analysis of these mensuration results showed that， the leaf color of Malus ‘Royalty and Malus ‘Guanghui was closely related to the ratio of pigments. When the ratio of anthocyanin to chlorophyⅡ dropped to 14，the leaf color of Malus ‘Royalty turned from red to green， so the color expression of leaves of Malus ‘Royalty was on account of anthocyanin degradation and chlorophyⅡaccumulation. The color expression of leaves of Malus ‘Guanghui was determined by anthocyanin content and carotenoids content， the leaf color of Malus ‘Guanghui turned from green to red when the ratios of anthocyanin to chlorophyⅡ increased to three and carotenoids accumulated. Soluble sugar offered material and energy for the synthesis of anthocyanin. PAL activity was closely related to the synthesis of pigments， but it might not be the key enzyme.

Key words： Malus baccata； leaf color change； anthocyanin

彩叶树种包括常色叶树种和季节性变色叶树种两类[1]。彩叶植物正是基于其自身优点，已经在世界各城市园林中广泛应用并成为世界园林植物贸易中的重要產业。

王族海棠（Malus ‘Royalty）和光辉海棠（Malus ‘Guanghui）均为蔷薇科苹果属落叶小乔木，其中王族海棠是从美国引进的常色叶海棠新品种，其叶片生育期为紫红色，极具观赏价值，是一种优良的紫红色叶树种[2]，但夏末秋初王族海棠常出现“返绿”现象，之后随着温度的降低，叶色逐渐由浓绿转变为紫红色。……