Evaluations of winter wheat late frost damage under different water based on principal component-cluster analysis
摘要
<p id="C3">To investigate the effect of low temperature at jointing stage on wheat physiological metabolism under different water conditions, a comprehensive physiological index is constructed to accurately evaluate the degree of freezing injury, which is of great significance to agricultural loss reduction, efficiency increase and macro management. Irrigation (W1) and no irrigation (W0) treatments were carried out one week before low temperature treatment using the weak-spring Yanzhan 4110 and Lankao 198, semi-winter Zhengmai 366 and Fengdecun 21 as the experimental materials. At the female and male ear differentiation stages, potted wheat was moved to the low temperature simulation room for low temperature treatment with six levels of normal (CK), -2℃ (T1), -4℃ (T2), -6℃ (T3), -8℃ (T4), and -10℃ (T5), respectively. The physiological indexes and fluorescence parameters were measured on the second day after treatment, and wheat yield was harvested at maturity stage. The results revealed that different varieties, water and low temperature stress, and their interactions had significant effects on wheat physiological indexes and fluorescence parameters at jointing stage. With the aggravation of low temperature stress, leaf water content, chlorophyll a content and fluorescence parameters <italic>q</italic><sub>p</sub>, <italic>F</italic><sub>v</sub>/<italic>F</italic><sub>m</sub>, and <italic>F</italic><sub>v</sub>/<italic>F</italic><sub>o</sub> showed the continuous downward trends, the contents of soluble protein, proline, soluble sugar, and SOD activity first increased and then decreased, but the content of MDA demonstrated the opposite trend. Irrigation treatment alleviated the influence of low temperature stress on plant physiological metabolism, and the effect of low temperature on semi-winter varieties was relatively lower. Four independent comprehensive indexes were transformed by the principal component analysis, which reflected 88.55% of the original informati