根际高温胁迫对6种瓜类作物幼苗生长和生理特性的影响
Effects of High Root-Zone Temperature on Growth and Physiological Characteristics in Six Cucurbit Crops

以黑籽南瓜(Cucurbita ficifolia Bouché)、‘甬砧8号’白籽南瓜(Cucurbita maxima×Cucurbita moschata ‘Yongzhen No.8’)、‘春秋王2号’黄瓜(Cucumis sativus‘Chunqiuwang No.2’)、日本南瓜(Cucurbita moschata)、‘五叶香’丝瓜(Luffa cylindrica ‘Wuyexiang’)和‘傲美’苦瓜(Momordica charantin ‘Aomei’)为试材,采用营养液栽培法,研究了25 ℃ (CK)和35 ℃ (H)根际温度下处理5 d及恢复5 d后,6种瓜类作物幼苗生长和生理特性变化。结果显示,与CK相比,35 ℃根际高温处理下6种瓜类作物的株高、茎粗、叶片数和叶面积都有不同程度的增长,日本南瓜和‘五叶香’丝瓜的生长量最大;同时6种瓜类作物的抗氧化酶活性、脯氨酸含量及丙二醛(MDA)含量显著升高,其中‘五叶香’丝瓜的脯氨酸含量升高了84.69%,升幅最大,MDA含量仅升高12.01%,升幅最小;6种瓜类作物的叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和根系活力明显降低,其中‘五叶香’丝瓜的净光合速率(Pn)和根系活力分别降低6.15%和1.33%,降幅最小;日本南瓜和‘甬砧8号’白籽南瓜叶片的胞间CO2浓度(Ci)升高,其他4种瓜类作物幼苗叶片的胞间CO2浓度(Ci)显著下降。上述结果表明,6种瓜类作物幼苗对根际高温的耐受性存在明显差异,其中‘五叶香’丝瓜最耐根际高温,可作为提高瓜类作物耐热性砧木加以利用。
To investigate the growth and physiological responses of 6 cucurbit crops to high root-zone temperature stress (H,35 ℃),seedlings of 6 cucurbit crops were exposed to H and 25 ℃ (CK) for 5 days and following with 5 days of recovery in hydroculture.The results showed that the plant height,stem diameter,leaf number,and leaf area of crops,especially Cucurbita moschata and Luffa cylindrica ‘Wuyexiang’,increased in H treatment compared with CK.Meanwhile,H significantly increased the activity of antioxidant enzymes,proline content and malondialdehyde (MDA) contents of the crops.The proline and MDA contents of Luffa cylindrica ‘Wuyexiang’ increased by 84.69% and 12.01%,respectively.The plant net photosynthetic rate (Pn),stomatal conductance (Gs),transpiration rate (Tr) and root activity decreased significantly during H treatment.The Pn and root activity of Luffa cylindrica ‘Wuyexiang’ decreased by 6.15% and 1.33%.The inter-cellular CO2 concentration(Ci) for Cucurbita moschata and Cucurbita maxima×Cucurbita moschata ‘Yongzhen No.7’ increased in H treatment,while the other four cucurbit crops decreased.The results demonstrated that different cucurbit crops have different tolerance to H stress.Luffa cylindrica ‘Wuyexiang’ exhibited the highest tolerance,which could be used as heat-resistant rootstocks for cucurbit crops.