关键词: 干旱胁迫, 根系形态, 生理特征, 红宝石海棠

Abstract: In order to study the effects of drought stress on root of Malus micromalus cv. ‘Ruby’, 1-year-old sapling of M. micromalus cv. ‘Ruby’ seedlings were selected as materials, 5 drought stress treatments including 85%±5% (CK), 70%±5% (T1), 55%±5% (T2), 40%±5% (T3), and 25%±5% (T4) were set up, the root morphology, activity and physiological characteristics of M. micromalus seedlings under different treatments were detected. The results showed that mild drought stress significantly increased root total length, surface area, total volume and root tips quantity of M. micromalus seedlings, and the continuous increase of drought stress intensity significantly reduced these morphological indexes. Root activity increased firstly and then decreased with the increase of stress degree, which of T4 decreased 15196% compared to CK. The contents of proline (Pro), soluble sugar (SS) and malondialdehyde (MDA) in roots increased with the increase of drought stress, those of T4 increased by 1.37, 1.68 and 2.82 times compared to CK, respectively. The content of soluble protein (SP) increased first and then decreased with the increase of drought stress degree. With the increase of drought stress, the activity of peroxidase (POD) in roots increased, however the activity of catalase (CAT) increased firstly and then decreased. Therefore, the appropriate water management measures should be formulated in the cultivation of M. micromalus. The relative soil water content should be maintained at the level of  more than 55%, otherwise, the development of root system and the growth of M. micromalus could be affected.

Key words: drought stress, root morphology, physiological characteristics, Malus micromalus cv. ‘Ruby’