西葫芦耐冷性生理指标研究

Studies on the Physiological Criteria for Cold Tolerance Evaluation in Cucurbita pepo L.

在耐冷性鉴定基础上， 测定了２２ 和５ ℃下８ 个西葫芦品系苗期电解质渗漏率、气孔阻力、光合速率以及叶绿素可变荧光（Ｆｖ） 和最大荧光（Ｆｍ） 比值。结果表明， 与２０℃处理相比，５ ℃处理下西葫芦幼苗电解质渗漏率和气孔阻力增大， 光合速率和Ｆｖ／Ｆｍ 下降。低温胁迫后， 电解质渗漏率的相对增加量与冷害指数呈极显著正相关， 光合速率及其恢复能力和Ｆｖ／Ｆｍ 及其恢复水平与冷害指数呈极显著负相关， 可以作为鉴定西葫芦品系耐冷性指标。

The electrolytic leakage(El),stomatal resistance(Sr),photosynthetic rate(Pn)and ratio of variable(Fv)and maximum(Fm)fluorescence(Fv/Fm)of seedling were measured after 5 and 20℃ treatment based on identifying cold tolerance at 3rd leaf age of 8 summer squash lines.The results showed that El and Sr increased whereas Pn and Fv/Fm decreased under 5℃ compared with 20℃.The relative increment of electrolytic leakage,Pn,recovery power of Pn,Fv/Fm and reco very level of Fv/Fm had highly significant correlation with chilling injury index(the coefficients were 0.9217,-0.9753,-0.9636,-0.9631 and -0.9893 respectively)after low temperature treatment,which could be used as the criteria to evaluate cold tolerance in summer squash.