Comparative Study On Alkali Resistance Of Different Azalea Cutivars

As the acidity and alkalinity of soil are important factors limiting the growth and production of plants,different concentrations of NaOH solution and H2SO4 solution were used to adjust soil pH values to 4 different levels(pH = 6.5,7.5,8.5,9.5).in order to promote the application of Azaleas,BaiYin,BaiChangchun,XiaoYing,XiaoXia,JinXiu,RuiZi,ZiXiu,XieJing,YaoFei,ShiYan,ShengChun,Yuanchun No.8,Yutangchun,WoLong No.1,Zhuangyuanhong,Ruozizi,Yanzhimi,Hongjingling,Jiangnanchunzao,and Zidongdongsheng were used as test materials to study the morphological characteristics,plant height growth,root/shoot ratio,water content and physiological changes of alkali damage index,chlorophyll content,plasma membrane permeability,osmoregulatory substances(soluble sugar,soluble protein),POD activity and photosynthetic characteristics when materials were under different pH soil treatments to explore the suitable range of soil acidity and alkalinity for the growth of R.simsii and provide theoretical guidance for its production and cultivation to promote industrial development,and the main findings are as follows:(1)The alkali-resistant screening pressure from the four alkaline stress concentrations of pH 6.5,pH 7.5,pH 8.5 and pH 9.5 based on the alkali damage index,and 20 rhododendron varieties.The results initially showed that the alkali damage index of XiaoYing,JinXiu,Yutangchun,Zhuangyuanhong,Ruoyinzi,Rouge Honey,Hongjing,Jiangnanchun early seven varieties is obviously lower than the remaining 12 varieties,and the alkali resistance ability is stronger.Violet,Yaohao and Yuanchun 8 have higher alkali damage index and poor alkali resistance.(2)Alkali stress inhibited the growth of Azalea.This inhibition was largely reflected in the increase in plant height,root/shoot ratio,water content,and root vigor.Under alkaline stress,the height increments of the seven cultivars such as JinXiu,Yutangchun,Zhuangyuanhong,Ruozizi,Ruzhimi,Hongjing and Jiangnanchunzao were larger,and the tolerance to alkali stress was the best.However,Rui Zi,Yao Xi,Shi Yan,and Yuan Chun No.8 had relatively small increases in plant height and were sensitive to alkali stress and poor in tolerance.In terms of water content and root/shoot ratio,the contents of Xiaoyan,JinXiu,Yutangchun,Zhuangyuanhong,Rouge Honey,Hongjing and Jiangnanchun are all higher,while those of Ruizi,Shiyan,Shengchun,and Yuanchun 8 are all higher.Lower.In terms of root vigor,the diazenamines of the seven cultivars JinXiu,Yu Tangchun,Long No.1,Zhuang Yuanhong,Bian Mi Mi,Hong Jing,and Jiangnan Chunzao had high reductive strength,indicating that the root activity was strong and they were subjected to alkali stress.The effect is small and the alkali resistance is strong;conversely,Ruizi,phantom,Shiyan,Shengchun,and Yuanchun 8 have low renaturation intensity,weak root activity,and poor tolerance to alkali stress under alkali stress.Weak ability.It can be concluded that the alkali-tolerant rhododendron species can maintain high root activity.Taken together,under alkaline stress,the growth indices of the six rhododendron varieties,ie,miracidia,Yutangchun,Zhuangyuanhong,Bengzhimi,Hongjing,Jiangnanchunzao are all higher,and they can tolerate certain alkali stress;The three varieties of Ruizi,Shiyan,and Yuanchun No.8 have low growth indicators,are sensitive to alkali stress,and have poor tolerance.(3)Under alkaline stress,the proline content,soluble sugar content and soluble protein content of 20 varieties were significantly different.Among them,the contents of three osmotic adjustment substances in the five species of raccoon,primrose red,rouge honey,red elves,and Jiangnanchun were all significantly lower than those of other cultivars,indicating that they were less affected by alkali stress,and the osmotic pressure was relatively stable.Strong anti-alkali ability;and Rui Zi,Yao Yao,Sheng Chun three varieties of three osmotic adjustment substances are higher,the osmotic adjustment system is seriously damaged,weak alkali resistance.(4)Under alkaline stress,the SOD activity and POD activity of all varieties showed significant differences.Among them,the activities of SOD in the four varieties,Ranunculus japonicus,Zhuangyuanhong,Bengzhimi and Jiangnanchunzao were significantly higher than those of other varieties,indicating that they were active under alkali stress and had strong alkali-tolerance;while Ruizi,Yaojing and Shiyan The four varieties of Shengchun,SOD activity and POD activity were significantly lower than other varieties,indicating that they are extremely resistant to alkali,poor alkali resistance.Under the same alkali stress,the contents of MDA in different varieties of azalea leaves were different.Among them,Maodan,Yutangchun,Zhuangyuanhong,Bengbu honey,and Jiangnanchun had five varieties of MDA that were lower in their early MDA content,indicating their strong alkali resistance.In Ruizi,YaoFei,Shiyan and Shengchun,their MDA content was relatively high,indicating that under alkaline stress,the permeability of cell membranes increased,electrolytes leaked out,and membrane lipid peroxidation products accumulated,MDA content increased,weak alkali resistance.(5)Under alkaline stress,there were significant differences in the relative conductivities of 20 rhododendron varieties.Among them,three varieties of edgy,primordial red,and rouge honey were found to have less electrolyte leakage in the cell membrane when exposed to alkali stress,while three species of Ruizi,Yaozhuo,Shiyan,and Shengchun exhibited electrolyte leakage from the plant cell membrane.In addition,the relative conductivity was high,the degree of alkali damage was high and the variety itself was weak in alkaline resistance.(6)Through the comprehensive evaluation of the 20 rhododendron varieties in different soil pH growth,alkali damage index,plasma membrane permeability,osmotic adjustment system,enzyme activity and other indicators,20 rhododendron varieties were evaluated for alkali resistance as:Alkali-resistant varieties included Rui Zi,Yao Fei,Shi Yan,Sheng Chun,and Yuan Chun No.8;5 varieties with relatively alkali-resistance included Xiao Ying,JinXiu,Yu Tang Chun,Zhuang Yuan Hong,Ruo Zi,Rouge Honey and Red Elves.There were 8 varieties in the early spring of Jiangnan and there were 7 varieties of Zixiu,Wolong 1,phantom,white seal,Bai Changchun,Xiaoxia and Ziqi Dong sheng.