高温胁迫对不结球白菜幼苗生长及生理指标的影响

A Study on the Relationship Between the Growth and Physiology of Pak choi and Heat Tolerance

根据多年夏季露地自然高温下的观察和36℃高温胁迫下的热害指数,筛选出了耐热品系196-3、197-5、196-8和198-9,不耐的品系197-7、196-12以及介于耐热和不耐热之间的品系197-4、197-6,并测定了这8个品系40℃高温胁迫下的膜稳定性;进一步在20℃/12℃(d/n)(ck)、32℃/20℃(d/n)、36℃/28℃(d/n)人工模拟高温胁迫条件下,测定了这8个品系的幼苗生长量、MDA、游离脯氨酸、游离氨基酸、以及总糖相对含量。结果表明:在32℃/22℃(d/n)和36℃/28℃(d/n)处理下,相对生长量、游离脯氨酸、游离氨基酸和总糖的相对含量品系间差异都极显著;相关分析表明,两温度处理条件下相对生长量与热害指数都极显著正相关,而只有32℃/22℃(d/n)处理条件下的游离脯氨酸、游离氨基酸和总糖的相对含量与耐热性存在显著的相关性,其中游离脯氨酸相对含量与耐热性呈极显著正相关(r=0.808 3**)。所以高温胁迫生理指标的研究中采用32℃/22℃(d/n)处理不结球白菜幼苗比36℃/28℃处理更能体现出品种间的耐热性差异。32℃/22℃(d/n)处理条件下的游离脯氨酸、游离氨基酸和总糖的相对含量都可以用来鉴定不结球白菜的耐热性,但是以游离脯氨酸为最好。

Experiments were performed to assess morphological and physiological effects of heat injury on hear-tolerant, intermediate and heat-sensitive pak choi lines, which were selected by years of field observation and the experiment of heat damage index. We tested hurt percentage on cell membrane under heat treatment of 40 ℃ ; relevant content of MDA under heat treatment of 32 ℃/22 ℃ （d/n） ; and we also tested the seedling relevant fresh and dry growth, dissociative proline, dissociative amino acid resolvable sugar under the heat treatment of 32 ℃/22 ℃ （d/n） and 36 ℃/28 ℃ （d/n）. The result is that under the temperatures of 32 ℃/22 ℃ （d/n） and 36 ℃/28 ℃ （d/n）, eight lines under test showed significant difference in the growth of both fresh and dry weight and showed significant correlation with heat tolerance. For the physiological indices, under both temperatures 8 lines showed significant difference in the relative content of dissociative proline, dissociative amino and acid resolvable sugar, but the correlation analysis indicated that only physiscreening of heat-tolerant breeding materials, and the relative content of dissociative proline, dissociative amino and acid resolvable sugar can be used as the criteria for the selection of heat tolerant pak choi, but the relative content of dissociative proline is the best one.