地被菊花幼苗耐旱性评价方法研究

A Simple Method to Evaluate the Drought Tolerance of Ground-Cover Chrysanthemum(Dentranthema×grandiflorum) Rooted Cuttings

选用地被菊品种White Snow 10 叶龄扦插生根幼苗进行自然失水胁迫和PEG 胁迫处理。划分了不同处理萎蔫指数,测定了鲜样质量保持率、叶片水势、叶片溶质渗透势、丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性。结果表明,萎蔫指数划分的主要形态特征因胁迫方法而异。自然失水胁迫8 h 为幼苗恢复极限;在恢复极限内复水,幼苗鲜样质量保持率、叶片水势、MDA 含量和SOD 以及CAT 活性的变化规律显著。20%PEG 胁迫4 h 为恢复极限;复水期间的鲜样质量保持率、叶片溶质渗透势、MDA 含量和SOD 活性的变化规律显著。综合上述,这2 种方法都可以用于地被菊花幼苗耐旱性快速评价;不同的胁迫处理方式可利用的水分状况和生理指标存在一定的差异。

This experiment was conducted with rooted cuttings of ground-cover chrysanthemum, Dentranthema×grandiflorum White Snow. The 10-leaf cuttings were exposed to dehydrations in air and osmotic adjustments of PEG, respectively. With the prerequisite of determination of wilting index (WI), fresh weight retention rate (FWRR), leaf water potential (LWP), leaf solute osmotic potential (LSOP), malondialdehyde (MDA) content, the activities of superoxide dismutase (SOD) and catalase (CAT) were measured. The main morphological characteristics to describe WI differed in both treatments. When the duration of dehydrations in air was less than 8 h, the cuttings could be recovered in 1/2 Hoagland and Arnon solutions, during which, the changes of FWRR, LWP, MDA content, SOD and CAT activity were related to drought tolerance of the cuttings. With 20% PEG treatment, the cuttings could be recovered normally in the recovery solution within 4 h stress, and the changes of FWRR, LSOP, MDA content, and SOD activity were related to drought tolerance. The above results suggested that both dehydrations in air and osmotic adjustments of PEG could be used to evaluate simply the drought tolerance of White Snow, and it differed in their available indices of water relations and physiology.