荒漠植物红砂抗旱性与其电学参数关系的研究

为了研究电学参数与红砂(Reaumuria soongorica)抗旱性的关系,以4个地理种源的荒漠植物红砂2年生苗木为材料,测定其茎在不同干旱胁迫处理下的高频电阻(r)、低频电阻(rl)、胞外电阻率(re)、胞内电阻率(ri)、电导(G)和电纳(B)等电学参数以及膜透性(RPP)和渗透调节物质脯氨酸(Pro)含量的变化,分析电学参数与膜透性和脯氨酸含量间的相关性。结果显示,随着干旱胁迫的加剧,4个地理种源红砂茎的膜透性和脯氨酸含量均呈逐渐升高或先升高后降低趋势,不同种源间存在显著差异(P0.05)。红砂茎膜透性的大小在4个种源间表现为:兰州张掖酒泉武威,脯氨酸含量由高到低依次为武威酒泉张掖兰州。4个地理种源红砂茎的高频电阻呈逐渐下降趋势,胞外电阻率、胞内电阻率、电导呈先升高后降低的趋势,而低频电阻则与它们相反,电纳的变化则较为复杂。6个电阻参数在不同种源材料间和不同处理间差异均显著(P0.05)。相关性和通径分析结果表明,胞外电阻率、胞内电阻率、高频电阻和电纳与膜透性的相关性较为明显;胞外电阻率、胞内电阻率、高频电阻和电导与脯氨酸含量的相关性较为显著,其中胞内电阻率对膜透性和脯氨酸含量的影响最大,通径系数绝对值分别高达0.938和0.897。说明电学参数ri可以作为表征红砂抗旱特性的参数,也表明电学方法将是荒漠植物逆境胁迫研究的一种有效方法。

Relationships between Drought Resistance and Electrical Parameters in Desert Plant Reaumuria soongorica

Electrical parameters such as resistance in high frequency (r), resistance in low frequency (r_l), specific extracellular resistance (r_e), specific intracellular resistance (r_i), value of conductance (G), susceptance (B) and relative permeability of plasma (RPP) and content of proline (Pro) in the stems of desert plant Reaumuria soongorica under drought stress from four provenances (Lanzhou, Zhangye, Jiuquan and Wuwei) were measured. The relationships between these electrical parameters and RPP and Pro were analyzed. Results showed that with increasing drought stress, stem RPP and Pro increased gradually or increased and then decreased. Significant differences existed among the four provenances (P < 0.05) for RPP in the order Lanzhou > Zhangye > Jiuquan > Wuwei and for Pro in the order Wuwei > Jiuquan > Zhangye > Lanzhou. The r of stem decreased gradually, r_e, r_i and G increased at first and then decreased, while r_l decreased at first and then increased. The variation of B was complex. The six electrical parameters differed significantly between provenance and drought stress treatments (P < 0.05). Correlation analysis and path analysis showed a significant correlation among r_i, r_e, r, B and RPP, and a significant correlation among r_i, r_e, r, G and Pro. However, RPP and Pro showed significant effects on r_i, with path coefficients of 0.938_RPP and 0.897_Pro, respectively. These results indicated that r_i was the best parameter for evaluating the drought resistance of R. soongorica stems and is an effective method for studying adversity stress in desert plants.