抗氟磺胺草醚生物型苘麻生物学特性研究OA

[Objective]This study aimed to clarify the fitness variation pattern of Abutilon theophrasti after developing resistance to fomesafen,providing scientific basis for predicting occurrence trend of resistant A.theophrasti in the field,formulating prevention and control strategies,delaying its spread,and ensuring safe production of crops.[Methods]The fomesafen-resistant population(LNZW)and susceptible population(LNHC)of A.theophrasti collected from different geographical regions in Liaoning Province were used to evaluate their sensitivity to fomesafen through whole-plant bioassay.Seed germination characteristics and seedling growth dynamics were compared with seed germination tests in the petri dish and seedling growth tests in the greenhouse.Photosynthetic physiological parameters were measured using a CIRAS-3 portable photosynthesis system to analyze differences of photosynthetic capacity between two biotypes.Combined with field experiments at different densities of A.theophrasti and intercropping with soybean,the vegetative growth and reproductive capacity of the two populations were systematically compared under non-competition,intraspecific competition,and interspecific competition to clarify the field ecological adaptability of resistant A.theophrasti.[Results]The sensitivity of LNZW and LNHC populations to fomesafen differed significantly,with a resistance ratio of 17.66.There was no significant difference in seed germination ability between the two populations(P>0.05).For seedling growth,plant height showed a transition at 17 days,and fresh weight showed a transition at 23 days:before these time points,the resistant population had lower plant height and fresh weight than that of the susceptible population,whereas after these time points,the resistant population surpassed the susceptible population.Differences in photosynthetic capacity were observed between the two biotypes.The net photosynthetic rate,intercellular CO ₂ concentration,transpiration rate,and stomatal conductance of the LNZW population were significantly higher than those of the LNHC population.After fomesafen application,the differences in photosynthetic parameters became more pronounced and increased with treatment duration.In greenhouse pot experiments throughout the whole growth period,except for stem diameter,vegetative growth and reproductive indices such as plant height and fresh capsule weight of the LNZW population were significantly higher than those of the LNHC population(P<0.05).In field competition experiments,both fresh weight per plant and capsule weight of A.theophrasti gradually decreased with increasing density under intraspecific competition.The fresh weight per plant and capsule weight of A.theophrasti grown alone were significantly higher than those of intercropping with soybean under interspecific competition.Regardless of intraspecific or interspecific competition,the LNZW population showed significantly higher vegetative growth and reproductive advantages than the LNHC population.[Conclusion]The fomesafen-resistant A.theophrasti exhibited no significant fitness cost,and the temporary growth cost at the seedling stage could be offset by compensatory growth at later stages.Higher photosynthetic capacity was an important physiological basis for maintaining its growth and reproductive advantages.Under intraspecific and interspecific competition,the LNZW population was significantly superior to the LNHC population in growth,reproduction,and ecological adaptability,demonstrating competitive advantages,a rapidly spread tendency and form dominant populations in the field.Integrated prevention and control strategies combining resistance monitoring,herbicide rotation,and field competition regulation should be formulated to curb its field damage and spread.