基于主成分-聚类分析的不同水分冬小麦晚霜冻害评价

探讨不同水分条件下拔节期低温对小麦生理代谢的影响,构建综合生理指数精确评价冻害程度,对农业减损增效和宏观管理具有重要意义。以弱春性的偃展4110和兰考198以及半冬性的郑麦366和丰德存21为材料,在低温处理前1周进行灌水和不灌水处理,于雌雄蕊分化期将盆栽小麦移至低温模拟室进行低温处理,分别为正常(CK)、–2℃(T1)、–4℃(T2)、–6℃(T3)、–8℃(T4)和–10℃(T5)。在处理结束后第2天测定小麦生理指标和荧光参数,在成熟期收获小麦产量。结果表明,不同品种、水分和低温胁迫及其互作对小麦拔节期生理指标及荧光参数均具有显著影响。随着低温胁迫加重,叶片含水量、叶绿素a含量及荧光参数qp、Fv/Fm和Fv/Fo呈持续下降趋势,而可溶性蛋白、脯氨酸和可溶性糖含量及SOD活性表现先升后降特征,但MDA含量则相反。灌水处理在一定程度上缓解了低温胁迫对植株生理代谢的影响,低温对半冬性品种的影响相对较小。利用主成分分析将测定参数转化成4个独立的综合指标,且反映了88.55%的原始信息,并构建出冻害生理综合指数(FIPCI)。聚类分析热图显示的颜色越深,生理指标响应程度越大。依据生理指标聚...

Evaluations of winter wheat late frost damage under different water based on principal component-cluster analysis

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 qp,Fv/Fm,and Fv/Fo 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 information,and the physiological comprehensive index of freezing injury(FICEI) was constructed.The depth of color in heat map indicated the darker the color,the greater the performance degree of indicators.According to the FIPCI value,the freezing injury was divided into five levels,which was consistent with the yield loss rate.Especially under T3 treatment,the yield loss rate of each variety reduced by 30.4%–44.0% under no irrigation,reduced by 21.0%–29.2% under irrigation treatment.Under the same irrigation condition,yield loss rate of different varieties was LK198>YZ4110>ZM366>FDC21,and the yield loss rate of semi-winter varieties was lower than that of weak spring varieties.According to the results of heat map clustering and the yield of each treatment,the yield loss rate was less than 10% for CK and T1,10%–30% for W0 T2,W1 T2 and W1 T3,30%–50% for W0 T3 and W1 T4,more than 50% for W0 T4,W0 T5 and W1 T5.Irrigating before low temperature was conducive to alleviating the damage caused by low temperature stress and reducing the yield loss.Physiological comprehensive freezing injury index and model constructed by principal component-cluster analysis can accurately evaluate the degree of wheat late frost damage,and provide scientific basis for yield recovery and decision-making management after disaster.