Study On The Regulation Of Culm Type In Phyllostachys Edulis F.tubaeformis

Internodal length is the important bamboo phenotypic trait,and it's also the key factor affecting the bamboo timber processing and utilization.Study on the bamboo's genetic mechanism of internodal length is meaningful both for its biology and its utilization.Phyllostachys edulis is the most wide-distribution,with largest area and highest economic value bamboo species in China,and the timber processing and utilization of Ph.edulis is the primary section in bamboo industry.To explore the genetic mechanism of internodal elongation,and then develop genetic improvement for Ph.edulis,many aspects of difference were studied by using the internodal shortened Ph.edulis f.tubaeformis and the internodal normal Ph.edulis,including their phenotypic,anatomical,fiber characteristics,and their carbohydrate and nitrogen metabolic,endogenous hormones,as well as transcriptome,moreover,exogenous hormones were applied to detect their variations of internodal length.The results were as follows:1.The phenotypic traits of Ph.edulis f.tubaeformis and Ph.edulis were measured and analyzed,the results showed that four traits of culm length,diameter at breast height,ground diameter and branch angle in Ph.edulis f.tubaeformis were significant lower than Ph.edulis,while five traits of culm node number,culm node number under branch,branch length,leaf length and leaf width demonstrated no difference between Ph.edulis f.tubaeformis and Ph.edulis.Correlation analysis demonstrated that difference at 1% or 5% significant level existed between culm length,ground diameter,diameter at breast height,culm node number,culm nodd number under branch,branch length,and also between leaf length and width,while branch angle have no correlation with other traits.The regressive model between the internode length and inernode numberical sequence of Ph.edulis f.tubaeformis and Ph.edulis were built as Y=3.016+0.438X-0.013X2 and Y=4.056+1.309X-0.011X2,respectively,its showed that with the increasing of inernode numberical sequence,the internode length of Ph.edulis f.tubaeformis increased more slowly than Ph.edulis.2.The culms of Ph.edulis f.tubaeformis and Ph.edulis were anatomized by paraffin-cut section,and their fiber characteristics were determined by nitrate-potassium chlorate method,the results showed that the fiber length and width were signifficantly different between Ph.edulis f.tubaeformis and Ph.edulis,for example,the fiber weigh weghted length means of Ph.edulis f.tubaeformis and Ph.edulis is 0.780 mm and 1.388 mm respectively,and the fiber width means of Ph.edulis f.tubaeformis and Ph.edulis is 19.404?m and 15.026?m.So the fiber morphology of Ph.edulis f.tubaeformis have shorter length,larger width.It was supposed it was the shorten of fiber length leads to the internode length shorten in Ph.edulis f.tubaeformis.3.The physiological features relating carbohydrate and nitrogen metabolism were studied by using young shoots and their sheaths of Ph.edulis f.tubaeformis and Ph.edulis,the results showed that the content of sucrose and fructose,and the activity of acid invertase in shoots of Ph.edulis f.tubaeformis were significant lower than Ph.edulis,while the activity of the activity of neutral invertase was significant higher than the latter,and the content of glucose had no significant difference.The content of protein and the activity glutamate dehydrogenase in shoots of Ph.edulis f.tubaeformis were significant lower than Ph.edulis,while ammonium nutrition content was significant higher than the latter,and the nitrate nitrogen content had no significant difference.Those carbohydrate and nitrogen characteristics in sheaths demonstrated no significant difference.The difference in carbohydrate and nitrogen demonstrated the physiological distinct in Ph.edulis f.tubaeformis and Ph.edulis.4.Endogenous hormones were detected in young shoots and their sheaths of Ph.edulis f.tubaeformis and Ph.edulis,the results showed that GA in upper,middle and basal part of shoots of Ph.edulis f.tubaeformis were significant lower than Ph.edulis;and BR in middle and basal part of shoots of Ph.edulis f.tubaeformis were significant lower than Ph.edulis;while ZT in upper of shoots of Ph.edulis f.tubaeformis were significant lower than Ph.edulis.So it was supposed that the internodal shortening of Ph.edulis f.tubaeformis maybe resulted by the coordination of ZT,GA and BR.5.RNA-seq were performed by using young shoots and their sheaths of Ph.edulis f.tubaeformis and Ph.edulis,the results showed that seven AP2 domain containing protein and one GASR7-gibberellin-regulated GASA/GAST/Snakin family proteins precursor were down expressed in Ph.edulis f.Tubaeformis,and the GASR7-gibberellin-regulated GASA/GAST/Snakin family protein precursor was highly expressed during internode elongation,and lowly expressed before internode elongation,and no expression after internode elongation.Therefore it was supposed that the internodal shorten of Ph.edulis f.tubaeformis might be related to the down expression of the GASR7-gibberellin-regulated GASA/GAST/Snakin family protein precursor.6.Exogenous hormones of GA3 and BR were applied to detect the variations of internodal length in of Ph.edulis f.tubaeformis.and Ph.edulis,the results showed th at exogenous applying GA3 and BR had no effect on the internodal elongation in Ph.edulis f.tubaeformis.,but exhibited significant difference in the internodal length betwe en Ph.edulis.