Comparative Study On The Growth Differences Between Lignified Bearing Shoot And Non-lignified Bearing Shoot In Jujube

Jujube(Ziziphus jujuba Mill.)is a unique fruit tree in China,and also a very important economic forest tree species.Lignified bearing shoot has excellent fruiting ability,which is the guarantee of improving yield of the southern fresh jujube.Two types of bearing shoot for Ziziphus jujuba cv.’Zhongqiusucui’ were used as materials.In this research,the phenological period,annual growth law and anatomical structure of stem of bearing shoot were observed,and the lignin small molecules and endogenous hormones of bearing shoot were qualitatively and quantitatively analyzed.The growth differences between the two types of bearing shoot were preliminarily discussed.The main results were as follows:1.Study on annual growth regularity of two types of bearing shoot.There were significant differences in the external morphology,phenological phase,growth period,fruit characteristics and quality between lignified bearing shoot and non-lignified bearing shoot.The budding time and the time of stopping growth of lignified bearing shoot was later than that of non-lignified bearing shoot,and the whole growth period was 25 days longer than that of non-lignified bearing shoot.Length,diameter and node number of lignified bearing shoot were significantly higher than those of non-lignified bearing shoot.The single fruit wight of lignified bearing shoot was higher than that of non-lignified bearing shoot.The internal quality of jujube fruit in lignified bearing shoot was better than non-lignified bearing shoot.2.Study on the anatomical structure of two types of bearing shoot.(1)The stem structure of two types of bearing shoot was amost the same,but there were also significant differences.The vascular bundle and cortex of stem for lignified bearing shoot are symmetrically distributed in cross section,while one side of vascular bundle and cortex for non-lignified bearing shoot expanded and distributed asymmetrically.(2)There were differences between anatomical parameters of stems for two types of bearing shoot,and the proportion of each structure parameter to the cross-sectional area of stem were also different.Xylem rate of lignified bearing shoot was higher than that of non-lignified bearing shoot from shoot growing stage to stop growing;Xylem rate and periderm rate of two types of bearing shoot were increased,and the differences were significant.3.Study on the difference of lignin synthesis between two types of bearing shoot.(1)The small lignin molecules content changed significantly at different stages.The relative contents of 4-coumaric acid,L-phenylalanine,sinapic acid,caffeate,coniferyl alcohol and coniferyl aldehyde changed significantly in middle internods of two types of bearing shoot;The relative contents of 4-coumaric acid,L-phenylalanine,sinapic acid,caffeate,cinnamic acid,coniferyl alcohol and coniferyl aldehyde had significant changes in basal internods of two types of bearing shoot.(2)Two monomers content in different internods of two types of bearing shoot was different in different periods.Lignin monomers content in lignified bearing shoot was higher than that in non-lignified bearing shoot at all stage.The degree of lignification in basal internods of lignified bearing shoot was higher than that of non-lignified bearing shoot.4.Study on the changes of endogenous hormones of two types of bearing shoot.(1)For lignified bearing shoot,ABA content in middle internodes decreased firstly and then increased,while increased firstly and then decreased in basal internodes.For non-lignified bearing shoot,ABA content in middle internodes decreased firstly and then increased;ABA content in basal internodes increased firstly and then decreased from shoot growing stage to fruit setting stage,and then increased slightly in fruit ripening period.(2)For lignified bearing shoot,IAA content in two internodes decreased over time.For non-lignified bearing shoot,IAA content in middle internodes decreased over time;IAA content in basal internodes increased firstly and then decreased.(3)For lignified bearing shoot,tZ content in middle internodes increased firstly and then decreased.tZ content in basal internodes decreased firstly and then increased.For non-lignified bearing shoot,tZ content in middle internodes and basal internodes increased over time.(4)For bearing shoot,higher level IAA,ABA and lower level tZ,higher IAA/ABA,IAA/tZ and lower level tZ/ABA were needed in shoot rapid growth period and full flowering stage.Higher level of tZ,lower level of ABA and higher level of tZ/ABA were needed in stop growing stage.