巨菌草对干旱胁迫的生理响应及相关性分析

Correlation Analysis and Physiological Characteristics of Pennisetum sp.Under Drought Stress

采用聚乙二醇(PEG-6000)模拟干旱胁迫的方法,研究了不同质量浓度PEG-6000胁迫后巨菌草叶片的生理特性变化,分析巨菌草的耐旱性,为巨菌草的应用和推广提供理论基础。结果表明:随着胁迫的加重,叶绿素和可溶性蛋白质含量下降,与胁迫质量浓度呈显著负相关;可溶性多糖(SS)含量升高,丙二醛(MDA)含量、过氧化物酶(POD)活性呈先升高后降低趋势,超氧化物歧化酶(SOD)活性、脯氨酸(Pro)含量先降低后升高,且5项指标变化均与胁迫质量浓度呈显著正相关;过氧化氢酶(CAT)活性呈先升后降趋势,与胁迫质量浓度无显著性相关。试验表明,巨菌草幼苗可忍受低于200g/L的PEG胁迫,此浓度范围内巨菌草可以通过3种酶的相互协调作用和调节渗透物质(可溶性多糖(SS)和脯氨酸(Pro)的含量)来减轻干旱伤害,并维持植物体的正常生理代谢功能,具有一定的抗旱能力。但浓度达到250g/L时,会对巨菌草幼苗造成严重干旱胁迫,甚至导致其死亡,250g/L是巨菌草幼苗抗旱的一个极限浓度。

To provide the academic basis of Pennisetum sp. application and popularization, and to analyzing drought resistame, physiological characteristics of Pennisetum sp. were studied under drought stress simulated by different concentration of PEG 6000. The results showed that, by the increase of stress level, the contents of soluble protein and chlorophyll decreased continuously, showing an obvious negative correlation with PEG stress; the content of soluble polysaccharide increased gradually;while the content of MDA or POD activity increased firstly and then decreased, the contents of proline and SOD activity decreased at beginning and then increased. Data of these five characters showed a significant positive correlation with PEG stress; the CAT activity increased firstly and then decreased, showing an insignificant positive correlation with PEG stress. These results indicate that Pennisetum sp. seedlings could stand less than the concentration of 200 g/L PEG and had a certain degree of drought tolerance. The interaction of three kinds of enzyme and osmatic adjustment substance （water soluble polysaccharide and proline） could be automatically managed to avoid the damage from water drought,which may induce potential ability of Pennisetum sp. against drought conditions. More than the concentration of 200 g/L PEG could bring Pennisetum sp. seedlings severe drought stress and even death.