土壤干旱胁迫对紫叶矮樱叶片呈色的影响

以盆栽3 a紫叶矮樱叶片为试材,采用称重控水法,设对照(土壤含水量18.11%)、轻度干旱(土壤含水量14.72%)、中度干旱(土壤含水量11.32%)和重度干旱(土壤含水量7.92%)4个处理组,研究不同土壤干旱条件下紫叶矮樱叶片呈色色素含量、可溶性糖含量、PAL酶活性的变化规律及其对叶片呈色的影响.结果表明:轻度干旱,随胁迫时间的延长叶片中花青苷、类黄酮、叶绿素、可溶性糖含量、PAL酶活性和a*增加, L*和b*降低;中度和重度干旱,随胁迫时间的延长花青苷、类黄酮、叶绿素、类胡萝卜素、可溶性糖含量、PAL酶活性和a*先增加再降低,L*和b*先减小再增大.短时间的干旱能够提高紫叶矮樱的叶片色泽,中度干旱15 d或重度干旱12 d,是紫叶矮樱叶色发生明显转变的关键时期;花青苷含量的变化是影响紫叶矮樱叶色变化的主要原因.

Effect of soil drought stress on leaf coloration-emerging of Prunus cistenena cv. Pissardii

The three-year-old pot-planted seedlings of Prunus cistenena cv. Pissardii were used to study the variation of leaf pigments, soluble sugar, activity of PAL, and coloration parameters under soil drought stress condition. The treatment design was control, slight drought stress, medium drought stress, and severe drought stress with relative soil water content of 18.11%, 14.72%, 11.32%, and 7.92%, respectively, which was artificially controlled by weighting. The results showed that the content of anthocyanin, flavonoids, chlorophyll, soluble sugar, activity of PAL, and "a*-value" were increased, and "L*-value" and "b*-value" were decreased under slight drought stress along with prolonged drought stress time. The content of main pigment, soluble sugar, activity of PAL, and "a*-value" were increased at first and then decreased, and "L*-value" and "b*-value" were decreased at first and then increased under medium and severe stress with prolonged drought stress time. The value of leaf coloration-emerging could be enhanced by short time drought stress, in which the key period of leaf coloration conversion was the 15th day under medium stress or the 12th day under severe stress. Anthocyanin was the key factor of leaf coloration-emerging in Prunus cistenena cv. Pissardii.