喷施拉肖皂苷C提高烟草幼苗抗干旱胁迫能力的生理机制

为了揭示具有油菜素甾醇功能的拉肖皂苷C(Laxogenin C,LG-C)提高烟草抗旱能力的生理机制,以豫烟10号为供试材料,采用叶面喷施的水培实验,检测干旱胁迫下喷施LG-C对烟草幼苗脂质过氧化物水平、渗透调节物质含量、抗氧化酶活性和光合特性的影响。结果表明,干旱胁迫处理后,烟草幼苗叶片丙二醛(MDA)的含量升高,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性增加,可溶性蛋白、脯氨酸、可溶性糖的水平都有不同程度的增加,而光合作用受到抑制。喷施外源LG-C提高了干旱胁迫下SOD、POD和CAT的活性,增加了渗透调节物质的积累,同时增加了叶绿素含量,提高了光合速率和叶片含水量,降低了MDA含量和相对电导率。因此,LG-C能够通过积累渗透物质、提高抗氧化酶活性、增强光合能力,进而缓解干旱胁迫对烟草幼苗的危害。

Physiological Achine of Laxogenin C on Increasing the Resistance to Drought Stress of Tobacco Seedlings

In order to reveal the physiological mechanism of laxogenin C (LG-C), which has the function of brassinosteroids and improving tobacco drought resistance, this paper took variety Yuyan 10 as material, conducted hydroponic experiment by spraying on leaf surface; and detected the effects of spraying LG-C on membranous peroxide level, osmotic regulation substances content, antioxidant enzyme activity, and photosynthetic characteristics of tobacco seedlings under drought stress. The results showed that drought stress treatment increased the leaf malondialdehyde (MDA) content of tobacco seedlings, improved the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and the content of soluble protein, proline, and soluble sugar, while the photosynthesis was restrained. Spraying exogenous LG-C under drought stress had improved the activity of SOD, POD, CAT and the accumulation of osmotic regulation substances; increased the chlorophyll content, photosynthetic rate and leaf moisture content; reduced MDA content and relative conductivity. Therefore, LG-C could alleviate the harm of drought stress on tobacco seedlings by accumulating osmotic substances, increasing activity of antioxidant enzymes, removing peroxide, and enhancing photosynthetic ability.