3种耐盐植物的根际微环境比较

研究了兰州市永登县秦王川灌区中型狼尾草(Pennisetum longissimum var.intermedium)、新疆大叶苜蓿(Medicago sativa)和皮燕麦(Avena sativa)对盐渍土的适应特点及其改盐效应。通过对3种植物不同生育期(播后90d、120d、150d)根际土壤pH值、导电率(EC)、盐分离子及有机质含量的测定,探讨盐渍化土壤影响下耐盐植物根际微环境的变化。结果显示:在盐渍化逆境下,3种植物对于根际土壤微环境均有一定调节作用,生育期内土壤pH值、EC值、Na+、SO2-4、Cl-和Ca2+含量逐渐降低,土壤有机质含量逐渐增加。新疆大叶苜蓿根际土壤pH值变化较为突出,其次是中型狼尾草和皮燕麦,播后150d较播前降幅分别为2.18%、2.06%、1.21%;中型狼尾草根际土壤EC值降幅最大,其次为新疆大叶苜蓿和皮燕麦,播后150d较播前降幅分别为42.69%、33.29%、28.33%;在3个取样期,中型狼尾草根际土壤Na+、SO2-4、Cl-含量变化幅度最大,新疆大叶苜蓿对Ca2+的吸收能力强于中型狼尾草和皮燕麦;中型狼尾草在生长期内根际土壤有机质含量持续增加,新疆大叶苜蓿在生长前期有机质增量较显著,生长中后期增量减缓,根际微环境变化趋于稳定。综合而言,中型狼尾草对盐渍土的适应及改良效应较突出,其次是新疆大叶苜蓿,再次是皮燕麦。

Comparison on Rhizospheric Microenvironment of Three Salt-tolerant Plants

Adaptation of Pennisetum longissimum var. intermedium, Medicago sativa and Avena sativa growing in saline soils in Qinwangchuan of Gansu, China was investigated by measuring the changes of rhizospheric pH value, electronic conductivity (EC), content of salt ions and organic matter at 90 d, 120 d and 150 d after sowing. The results showed that the three plants had adjustment effects on saline soil microenvironment, which were proved by decreases of the pH, EC, content of Na⁺, SO₄^2-, Cl^- and Ca²⁺ and increases of the content of organic matter progressively during the whole growth period. Medicago Sativa had the greatest effect on pH, the next was Pennisetum longissimum var. intermedium, followed by Avena sativa, decreased by 2.18%, 2.06% and 1.21% at 150 d after sowing, respectively. Pennisetum longissimum var. intermedium was found with the greatest effect on EC, the next was Medicago sativa, followed by Avena sativa, decreased by 42.69%, 33.29% and 28.33% at 150 d afer sowing, respectively. During the growth period, the changes in the content of Na⁺, SO₄^2- and Cl^- were the greatest for Pennisetum longissimum var. intermedium, while Medicago sativa had better absorption for Ca²⁺. The content of organic matter increased continuously within the whole growth period for Pennisetum longissimum var. intermedium. A significant increase of the content of organic matter for Medicago sativa was found during earlier growth stage, which slowed down during medium and later growth stages. In conclusion, Pennisetum longissimum var. intermedium had the best adaptation and improvement capacity in saline soil, followed by Medicago sativa and Avena sativa.