Studies On The Influencing Factors And Physiological Mechanism Of Tillering Ability Of Ramie

Ramie tiller is developed from terminal bud of underground stem or axillary bud of scale leaf on node.The number of tiller is directly related to ramie yield.In order to understand the effect of meteorological factors on tiller ability,the differences of tiller of different ramie varieties,and the relationship between endogenous hormones and physiological indexes and tiller,this study was carried out through the following three experiments:(1)Using three main ramie cultivars as materials,the tiller number and economic traits were investigated for 11 consecutive years(2010-2020).Combined with meteorological data during the growth period,the interannual changes of tiller number and the influence of meteorological factors on tiller number were investigated.(2)Twenty-six ramie varieties were used as materials to conduct field micro-area experiments.Each variety was repeated three times.The tiller number and agronomic traits of ramie in each season were measured for three consecutive years(2018-2020),to explore the differences in tiller ability of different varieties,to classify the tiller ability,and the correlation between tiller ability and agronomic traits indexes.(3)On the basis of experiment 2,three germplasms with large differences in tiller ability were screened,and the endogenous hormones(IAA,GA3,ZR),total nitrogen content,soluble sugar content,soluble protein content and chlorophyll content of functional leaves during the growth period were determined to explore the relationship between endogenous hormones,physiological indexes and tiller ability of ramie.The aim was to provide theoretical basis for high-yield cultivation and physiological and biochemical mechanism of ramie.The main results are as follows:1.The yield and agronomic traits of Xiangzhu no.3,Zhongzhu No.1 and polyploidy No.1 were different in 11-year ramie positioning experiment.The tiller number of the three cultivars fluctuated up and down.The first season ramie,sunshine duration in May had a greater effect on yield and effective plant rate,while temperature and sunshine duration in March had a greater effect on stem diameter.Average temperature and minimum temperature in May had great influence on plant height.The maximum temperature in April and rainfall in May had great influence on the flax rate of fresh peel.The second season ramie,the minimum temperature in July was the main meteorological factor affecting tillers number.Minimum temperature,relative humidity and wind speed in July were the main meteorological factors affecting plant height.Rainfall and wind speed in July were the main meteorological factors affecting stem diameter.Average temperature and maximum temperature in June were the main meteorological factors affecting fresh skin thickness.The maximum temperature in June,rainfall and minimum temperature in July had great influence on the flax rate of fresh skin.In the third season of ramie,meteorological factors had little effect on tillering number;Average temperature,maximum temperature,minimum temperature in August and relative humidity in October had a significant effect on yield.The effective tiller rate was greatly affected by the minimum temperature and relative humidity in August.The maximum temperature and relative humidity in October had great influence on plant height.Average temperature,minimum temperature and wind speed in August had great influence on stem diameter.2.From 2018 to 2020,the results showed that tillering ability of different cultivars differed significantly.Among 26 cultivars,the tillering ability of Bijie Yuanma was the highest,while that of Liuyang Dayexiang was the lowest.The difference of tiller number among varieties was 1～1.5 times.By cluster analysis,the26 cultivars were divided into three categories of high,medium and low plant strength,namely,bijie Yuanma,Huazhu 4 and Lechang Huangpi Zhu with high tillering capacity.Liuyang Dayyexiang,Zixi Ma,Yuanjiang Huangkehan,Xiangzhu no.3,Dayong Huangkema,Zhongzhu No.1,Polyploid No.1,Wugang Houpima,Xiangzhu No.7,Linshui Qingdingjiama,Chuanzhu No.8,Yuanjiangchishan Xijiangba,the varieties with moderate tillering ability were Wugang Hongpizhong,Yuanjiang Chaihuoma,Dongkou Qingma,Changsha Qingyema,Huazhu No.5,Pingjiang Zongdouma,Zunyi Tuandouma,Changshun Goupima,Ningxiang Chongtianpao and Zhejue Ramie.Correlation analysis showed that tiller number had a significant positive correlation with raw hemp yield,and the correlation coefficient was 0.313.Tiller number was negatively correlated with plant height and stem diameter,and the correlation coefficients were-0.328 and-0.447,respectively.Path analysis showed that fresh skin yield directly affected raw flax yield,and the direct path coefficient was 1.095,while tiller number,plant height,stem diameter,fresh skin thickness and other traits indirectly affected raw flax yield by increasing fresh skin yield.3.The varieties with high plant strength developed faster and had more tillers.The contents of IAA,GA3 and IAA/ZR were low and ZR was high in the varieties with high tiller ability.Correlation analysis showed that tiller number had a significant negative correlation with IAA content,GA3 content and IAA/ZR value in different tiller stages,and a significant positive correlation with ZR content in leaves.4.The chlorophyll content,sugar/nitrogen ratio and soluble sugar content in leaves of ramie with high plant strength were higher than those of the other two varieties,while the total nitrogen content in leaves was lower than that of the other two varieties.There was no significant difference in soluble protein content among varieties.Correlation analysis showed that there was no significant negative correlation between plant number and total nitrogen content and soluble protein content,but significant positive correlation with soluble sugar content,sugar-nitrogen ratio and chlorophyll content.