摘要
Pennisetum centrasiaticum is widely distributed in arid and semi-arid areas of Tibet. Its rhizome system is developed and has strong resistance to adversity. In this study, the physiological characteristics and drought resistance of P.centrasiaticum seedlings from 12 drought-stressed sites in Tibet were examined at the Lhasa Plateau Ecosystem Research Station of the Chinese Academy of Sciences. PEG-6000 solution with five levels of water potential(0, –0.7, –1.4, –2.1, and –2.8 MPa) was used to simulate drought stress, and malondialdehyde(MDA), proline(Pro) and chlorophyll contents were determined. The balance between production and elimination of reactive oxygen species in P.centrasiaticum was destroyed, leading to membrane lipid peroxidation and the production of MDA, and accelerating the decomposition of chlorophyll. P.centrasiaticum absorbed water from the outside to resist drought by secreting proline and other osmotic regulating substances. The Pro and chlorophyll contents in P.centrasiaticum showed a temporary rising trend, and then decreased with the decrease in water potential. MDA content increased with the decrease in water potential. By using the membership function method, the drought resistance of P.centrasiaticum seedlings from the 12 areas was evaluated, and the results showed that the drought resistance at the sites went from strong to weak in this order: Xietongmen > Linzhou > Sog > Damxung > Tingri > Namling > Gyirong > Linzhi > Purang > Dingjie > Longzi > Sa’gya. The drought resistance of P.centrasiaticum was strong in Xietongmen, Linzhou and Sog. Whether P.centrasiaticum from these three areas is suitable for cultivation in arid and semi-arid areas of Tibet needs further study.
白草广泛分布在西藏干旱、半干旱地区,其根茎系统发达,抗旱能力较强。本文以西藏12个地区的野生白草为材料,在中科院拉萨高原农业生态综合试验站研究野生白草幼苗在干旱胁迫下的生理特性,并用隶属函数法对抗旱性进行综合评价,拟筛选出抗旱能力较强的白草种类。实验采用5种不同水势(0,–0.7,–1.4,–2.1,–2.8 MPa)的PEG-6000溶液模拟干旱胁迫,测定12份白草幼苗体内丙二醛(MDA)、脯氨酸(Pro)和叶绿素等生理指标。结果表明,随着水势的下降,白草体内活性氧的产生和消除平衡受到破坏,导致膜脂过氧化,产生丙二醛,加速叶绿素的分解;通过脯氨酸等渗透调节物质从外界吸水来抵御干旱。随着干旱胁迫的加剧,丙二醛的含量总体呈上升趋势,脯氨酸和叶绿素的含量总体呈先升后降趋势。利用隶属函数法对12个地区白草幼苗的抗旱性进行综合性评价,研究得出抗旱性由强到弱依次为:谢通门>林周>索县>当雄>定日>南木林>吉隆>林芝>普兰>定结>隆子>萨迦,表明谢通门、林周和索县白草的抗旱性较强,其是否适宜在西藏干旱、半干旱地区种植尚需进一步研究。
基金
The National Key Research and Development Program of China(2016YFC0502005)
The Tibet Science and Technology Major Projects of the Pratacultural Industry(XZ201901NA03)
The Lhasa Industrial Integration Project(XCKJ004)
Research and Demonstration on the De-velopment Model of Forage Industry in Dagze County(LSKJ2018006)。
