紫色土干旱胁迫对栀子生长及生理的影响

Effects of drought stress on growth and physiological indexes of Gardenia jasminoides in purple soil

为探讨栀子对紫色土干旱胁迫的响应,以1年生栀子实生苗为试验材料,采用盆栽称重控水法在紫色土基质中对栀子幼苗进行轻度、中度及重度3个水平的干旱胁迫,探讨紫色土干旱胁迫对栀子的生理特性等的影响。结果显示:紫色土干旱胁迫对栀子幼苗的生长具有一定的抑制作用,栀子的主要生理指标发生明显变化以抵抗干旱的伤害。随着干旱胁迫的加剧,栀子的苗高和地茎呈现出不同程度的减小趋势;轻度和中度胁迫处理的栀子的苗高和地径减小程度较低。在轻度干旱下,栀子叶片相对电导率和丙二醛含量在整个胁迫期间增幅较小,分别仅为5.45%和7.39μmol·g^(-1)。随着干旱胁迫时间增加和胁迫加剧,栀子超氧化物歧化酶和过氧化物酶活性均先升后降,表明这两种酶在栀子生理防御系统中具有协同功能;在轻度干旱下,栀子超氧化物歧化酶和过氧化物酶活性变幅较小,分别为90.92 U·g^(-1)和107.23 U·g^(-1)·min^(-1)。可溶性糖和游离脯氨酸作为植物体内渗透压调剂物质随着干旱胁迫的增强表现出逐渐增加的趋势,以提高植株细胞的吸水功能,缓解植物因外界干旱而受到的损伤。本研究结果说明栀子在一定干旱胁迫下相关生理代谢受阻较小,能够维持植株的正常生理活动,可作为紫色土区域植被恢复树种推广应用。

In order to explore the response of Gardenia jasminoides to the drought stress in purple soil,the one-year-old seedlings were used as the experimental material,and the potted weighing and water control method was used to carry out different degrees of drought stress on the seedlings in purple soil substrate.The effects of drought stress on the physiological characteristics of seedlings were discussed.The results showed that the drought stress of purple soil had a certain inhibitory effect on the growth of G.jasminoides seedlings,and the main physiological indexes changed significantly to resist the damage of drought.With the intensification of drought stress,the height and stem of the seedling showed a trend of decreasing to different degrees,and the decrease of height and ground diameter treated with mild and moderate stress was lower.Under mild drought,the relative conductivity and malondialdehyde content increased slightly during the whole stress period,only 5.45%and 7.39 jxmol*g 1,respectively.With the increase of drought stress time and the intensification of stress,the activities of superoxide dismutase and peroxidase increased firstly and then decreased,indicating that these two enzymes had synergistic functions in the physiological defense system of G.jasminoides.Under mild drought,the activities of superoxide dismutase and peroxidase changed slightly,which were 90.92 U·g^(-1)and 107.23 U·g^(-1)·min^(-1),respectively.Soluble sugar and free proline as osmotic pressure regulators in plants showed a gradual increase trend with the enhancement of drought stress,so as to improve the water absorption function of plant cells and alleviate the damage received by plants due to external drought.The results of this study indicated that the physiological metabolism of G.jasminoides was less hindered under certain drought stress,which could maintain the normal physiological activities of the plants,and could be popularized and applied as a tree species for vegetation restoration in purple soil area.