[Objective]This study aims to explore the physiological mechanism behind the poor mechanical bearing capacity of Yunyan 121 leaf stalks.[Methods]Taking the main flue-cured tobacco variety(K326)as the control,the study examined the mechanical bearing capacity of Yunyan 121 leaf stalks,root development,and elongation.The root development was further promoted by exogenous application of growth auxin analog 1-naphthaleneacetic acid(NAA)or the nitric oxide precursor sodium nitroprusside(SNP),subsequently observing changes in leaf mechanical bearing capacity.[Results](1)Yunyan 121 had a higher fresh weight of leaves than the control variety K326,but its leaf stalk vascular bundle area and maximum leaf load-bearing capacity were 46％and 16％lower,respectively,compared to K326..(2)The root system of Yunyan 121 was underdeveloped,with the number of primary lateral roots and average length being 21％and 36％lower,respectively,compared to K326.(3)Exogenous application of NAA or SNP under greenhouse pot conditions significantly promoted the formation and elongation of the first-order lateral roots in both flue-cured tobacco varieties,thereby significantly increasing the leaf stalk vascular bundle area and maximum leaf load-bearing capacity.(4)Correlation analysis showed that the growth indicators of the root system were significantly positively correlated with both the leaf stalk vascular bundle area and the maximum leaf load-bearing capacity.(5)Compared with the control,exogenous NAA application under field conditions significantly promoted root growth of Yunyan 121,and the maximum leaf load-bearing capacity also significantly increased.[Conclusion]A smaller vascular bundle area in leaf stalks is the direct cause of the low mechanical bearing capacity in Yunyan 121 leaf stalks.Promoting the formation and elongation of primary lateral roots of Yunyan 121 can increase leaf stalk vascular bundle area and bending resistance.
关键词
根系/叶柄机械承受能力/维管束面积
Key words
root/petiole mechanical strength/vascular bundle area
维普
万方数据