LI Jian-YongGUO Shang-JingLI Xin-GuoMENG Jing-Jinga...
35-39,56页查看更多>>摘要:We have repotted that the roots of fig, leaf gourd (Cucurbita ficifolia, as rootstock) could improve the resistance of cucumber seedlings (Cucumis sativus L.cv. Jinyan 4, as scion) to 6 h stress at low temperature and low irradiance [1]. In this experiment, the relationship between the mineral elements uptake and photosynthetic activity of photosystems in figleaf gourd and cucumber seedlings were to be studied during low temperature (8 C) stress under low irradiance (100 μ. mol m-2 s-1 PFD) for 5 days. Compared with control seedlings, the maximal photochemical efficiency of PS2 (Fv/Fm) and the oxidizable P700 (P700+) of both figleaf gourd and cucumber seedlings decreased, and beth Fv/Fm and P700+ were lower in cucumber leaves than in figleaf gourd seedlings at the end of the stress. Superoxide dismutase (SOD) activity was higher in beth leaves and roots of figleaf gourd than in leaves and roots of cucumber at both room temperature and low temperature. However, the product rate of O 2 was lower in figleaf gourd leaves than in cucumber leaves. Upon ex-posure to the stress, the malondialdehyde (MDA) content increased markedly in leaves and roots of figleaf gourd and cucumber seedlings, and it grew faster in cucumber seedlings than that in figleaf gourd seedlings. Under adaptive conditions, some mineral elements (Such as Cu, Zn, Mn and Mg) have different contents in leaves and roots between figleaf gourd seedlings and cucumber seedlings. However, at the end of the stress these elements were accumulated apparently in both leaves and roots of figleaf gourd accompanied by no obvious change in cucumber seedlings.