半夏对3种常见农作物的化感作用及其生理机制研究

Effects and physiological mechanisms of allelopathy of Pinellia ternata(Thunb.)Breit on three common crops

【目的】从化感作用角度筛选适宜与半夏[Pinellia ternata(Thumb.)Breit]进行轮间作的农作物,为建立合理的半夏轮间作体系提供参考依据。【方法】采用水提法制备半夏地上部和地下部提取液,每种提取液设5个浓度梯度[0(CK)、0.025、0.050、0.100和0.200 g/mL],研究半夏不同部位浸提液对3种主要经济作物玉米(Zea mays Linn.sp.)、萝卜(Raphanus sativus L.)和白菜(Brassica pekinensis)的化感效应。【结果】低浓度(0.025 g/mL)半夏提取液对3种农作物的生长整体表现为轻微促进作用。高浓度(0.200 g/mL)的半夏提取液对3种农作物均表现出较强的化感抑制作用,主要表现为幼苗生长受到抑制,叶片中的叶绿素和类胡萝卜素合成受阻;光合色素比例调整,整体表现为叶绿素a/b上升和叶绿素/类胡萝卜素比值下降;抗氧化酶[过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)]活性和可溶性蛋白含量降低,膜脂过氧化产物丙二醛(MDA)含量升高。3种农作物对半夏化感作用的敏感程度由高到低依次为萝卜>白菜>玉米。【结论】半夏的化感物质主要集中于地下部块茎中,其化感作用会影响受体作物的光合作用效率及抗氧化系统稳定性;3种农作物中玉米最适合与半夏进行轮间作。

【Objective】The crops which are suitable for intercropping or rotating with Pinellia ternata(Thunb.)Breit were screened based on allelopathy to provide theoretical basis for establishing efficient model of P.ternata intercropping or rotation system.【Method】Extraction solutions of shoots and roots of P.ternata were obtained through water extraction method.Five concentrations of extraction solution[0(CK),0.025,0.050,0.100,and 0.200 g/mL]were used to study the allelopathic effects of P.ternata extraction solution from different parts on three economic crops(Zea mays Linn.sp.,Raphanus sativus L.and Brassica pekinensis).【Result】Low concentration(0.025 g/mL)water extracts of P.ternata showed a slight stimulative effect on the seedling growth of the three crops.Whereas the high concentration(0.200 g/mL)water extracts of P.ternata showed strong inhibitory effect on seedling growth of the three recipient crops and led to the inhibition of chlorophyll(Chl)and carotenoid(Car)synthesis in crop leaves.What was more,the ratios of Chl a/b increased and the ratios of Chl/Car decreased on the whole.Meanwhile,content of soluble protein(SP)and activity of antioxidant enzymes such as catalase(CAT),peroxidase(POD)and superoxide dismutase(SOD)decreased,and the content of malondialdehyde(MDA)increased.The sensitivities of three crops to allelopathy of P.ternata followed the order of R.sativus>B.pekinensis>Z.mays.【Conclusion】Allelochemicals of P.ternata were mainly stored in underground tubers.Allelopathy of P.ternata has influence on photosynthetic efficiency and antioxidant system stability of recipient crops.Z.mays is the best choice to intercrop or rotate with P.ternata among the three crops.