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为了掌握持续干旱胁迫下外源精胺(Spm)对红椿幼苗的形态和生理调节效应,本研究以2年生红椿盆栽幼苗为试验对象,在人工遮雨棚中开展干旱胁迫及外源精胺调节试验,试验设置4个持续干旱胁迫处理:(1)对照(土壤相对含水量45%~50%,每天浇水至饱和状态,CK);(2)轻度干旱胁迫(土壤相对含水量30%~38%,持续干旱7 d);(3)中度干旱胁迫(土壤相对含水量25%~30%,持续干旱14 d);(4)重度干旱胁迫(土壤相对含水量20%~25%,持续干旱21 d)。然后,连续3天对轻度、中度和重度干旱胁迫处理喷施外源Spm(浓度为1 mmol·L-1)进行修复调节,并正常管护5天。结果表明:喷施Spm对重度干旱胁迫下植株形态损伤的修复速度远低于轻度和中度干旱胁迫植株;在对照、轻度干旱胁迫(或中度、重度)以及喷施外源Spm调节三者之间,红椿幼苗叶片相对含水量和叶绿素含量均差异极显著(P<0.01);在对照、中度干旱胁迫(或重度)以及喷施外源Spm调节三者之间,红椿幼苗叶片相对电导率均差异极显著(P<0.01);在对照、轻度干旱胁迫以及喷施外源Spm调节三者之间,红椿幼苗叶片MDA含量和POD含量差异显著(P<0.05);在对照、重度干旱胁迫以及喷施外源Spm调节三者之间,红椿幼苗叶片MDA含量和POD含量差异极显著(P<0.01);在对照、重度干旱胁迫以及喷施外源Spm调节三者之间,红椿幼苗叶片游离脯氨酸含量差异极显著(P<0.01);喷施1 mmol·L-1Spm可修复红椿在遭受干旱胁迫时造成的形态和生理损伤并提高植株的持续抗旱能力,其修复作用对轻度和中度干旱胁迫更为显著。
In order to understand the morphological and physiological regulation effects of exogenous spermine (Spm) on the seedlings of Toona sinensis under continuous drought stress, in this study, the seedlings of two-year-old Toona sinensis seedlings were used as experimental subjects. Drought stress and exogenous (1) Control (soil relative water content 45% ~ 50%, daily watering to saturation state, CK); (2) Light drought stress (soil relative water content Moderate drought stress (25% -30% of soil relative water content, continuous drought for 14 days); (4) Severe drought stress (soil relative water content of 20% ~ 30% 25%, continuing drought 21 d). Then, exogenous Spm (concentration of 1 mmol·L-1) was sprayed and reconstituted for 3 days on a mild, moderate and severe drought stress condition and maintained for 5 days. The results showed that the spraying rate of Spm was significantly lower than that of mild and moderate drought stress plants under severe drought stress. Under the control, mild drought stress (moderate or severe) There were significant differences in the relative water content and chlorophyll content between the three treatments (P <0.01). Under the control, medium drought stress (or severe) (P <0.01). Under the control, mild drought stress and exogenous Spm regulation, the content of MDA and POD in leaves of Toona sinensis seedlings had significant difference (P <0.05) ; In the control, severe drought stress and Spraying exogenous Spm regulation, the content of MDA and POD content of Toona sinensis seedling leaves were significantly different (P <0.01); in the control, severe drought stress and Spraying exogenous Spm regulation The content of free proline in the leaves of Toona sinensis seedlings had significant difference (P <0.01). Spraying 1 mmol·L-1Spm could repair the morphological and physiological damage of Toona sinensis under drought stress and increase the content of Sustained drought resistance, its repair effect on mild and moderate drought stress It is significant.