Characteristics of Premature Aging Induced by Lesion-Mimic Mutant lmpa1 in Wheat
In this study,the wheat line KD527 and its lesion-mimic premature aging(LMPA)mutant lmpa1 induced by EMS and also their F1 and F2 populations were used as materials,the occurrence and mor-phology of lesion-mimic as well as the agronomic and yield traits were analyzed,the photosynthesis indices were detected,and histochemical staining identification were carried out,in order to illustrate the physiologi-cal and biochemical mechanisms of premature agingin lmpa1.The results showed that KD527 could complete the growth and maturation processes normally.The mutant lmpa1 grew normally in early period,but the photo-inducedlesion-mimic reaction occurred after flag leaf lifting,with appearance of yellow-brown lesion-mimic spots on leaves;the spots spreaded to the leaf sheath,stem and ear gradually with the extension of growth pe-riod,which caused premature senescence of the whole plant until dried up and died,and led to yield reduc-tion ultimately.During the occurrence of lesion-mimic reactions,the net photosynthetic rate,stomatal conduct-ance,and transpiration rate in leaves of lmpa1 were significantly lower than those of KD527 while the intercel-lular CO2 concentration was significantly higher(P<0.01).The total chlorophyll content in lmpa1 was signifi-cantly lower than that in KD527,and the differences increased with the severity of the lesion-mimic occur-rence.In the early stage of lesion-mimic,the content of hydrogen peroxide(H2 O2)and activities of catalase(CAT),superoxide dismutase(SOD)and peroxidase(POD)in leaves of lmpa1 are higher than those in KD527;as the lesions spread,the activities of CAT,SOD and POD decreased sharply,while the content of H2 O2 increased quickly.Cell deaths were detected at sites of the lesion-mimic by histochemical staining analy-sis.The conclusions above could lay theoretical foundations for physiological and biochemical mechanisms of Lmpa1 inregulating premature aging of wheat.
WheatLesion-mimic-type premature agingMutant lmpa1Physiology and biochemistryPhotoinduction
万方数据
维普
