摘要 : The effects of infections of Barley yellow dwatf virus BYDV, Fusarium culmorum and/ graminearum alone as well as double infections of BYDV and Fmarium spp, on assimilation of 14CO2 by flag leaves and ttanslocation of photosynthate... 展开 The effects of infections of Barley yellow dwatf virus BYDV, Fusarium culmorum and/ graminearum alone as well as double infections of BYDV and Fmarium spp, on assimilation of 14CO2 by flag leaves and ttanslocation of photosynthates in winter wheatcultivars 'Agent' susceptible to Fusarium head blight FHB and Tetrus' moderately resistant to FHB were studied in outdoor pot experiments in 2001 and 2002. Wheat plants were inoculated with BYDV-PAV strain by Rhopalosiphum padi at growth stage GS51 in 2001 and at GS 39 in 2002 Control plants were inoculated with virus free aphids. In the middle part of spikes single florets of wheat plants of both cvs were inoculated at GS 65 with conidia suspensions of F. culmorum in 2001 and F. graminearum in2002. Exposure of flag leaves with I4CO2 revealed that photosynthetic fixation was most pronounced at GS 71 and declined from GS 75 to GS 85 F. culmorum infections diminished absorption of 14CO2 by flag leaves in cv, 'Agent' and very low percentages ofphotosynthates were transported into the middle and upper head parts, while absorption of 14CO2 in cv. 'Petrus' was only slightly reduced and high proportions of 14C assimilates were translocated also into the middle and upper spike sections. BYDV infections markedly reduced 14CO2 assimilation by flag leaves and export of photosynthates into wheat spikes of both cvs, especially in cv. 'Petrus'. In double infected plants BYDV and Fusarium spp., photosynthetic fixation by flag leaves of both cvs at thefirst and second exposure times corresponded with that of BYDV-infected plants. However, export of assimilates in spikes was more effectively reduced in cv. 'Agent' than in cv. 'Petrus' Preinfestation with R padi slightly reduced assimilation of 14CO2 inboth cvs. In cv. 'Agent', translocation of 14C assimilates into the upper spike section was more impaired than in cv, 'Petrus'. Assimilation of 14CO2 and distribution pattern of 14C assimilates in R./zaf/-preinfested plus Fusarium-iafeaed plants of both cvs resembled that of fungus-infected plants at the first two exposure times.Absorption of 14CO2 by flag leaves and translocation of assimilates into spikes was markedly affected by severity of virus infection. The earlier BYDV inoculation in 2002 atGS 39 resulted in more severe virus infection and, therefore, drastically diminished 14CO2 absorption by flag leaves and translocation of photosynthates into spikes compared to 2001 when wheat plants were inoculated at GS 51The differential translocation of photosynthates into Fusarium-mfected spikes of the two cvs 'Agent' and 'Petrus' reflects the varying susceptibility of both cvs to FHB The studies also revealed severe effects of BYD-disease on FHB development. This interaction may result in practical consequences. 收起