@article{HE2023, 
author = {Xiaosan HE and Wencai ZHOU and Fengying QIU and Chun GONG and Linchu XU and Xiangyuan XIAO and Yujuan WANG},
title = {Responses of different Camellia oleifera varieties to drought stress and the comprehensive evaluation of their drought resistance},
year = {2023},
journal = {Journal of Central South University of Forestry & Technology},
volume = {43},
number = {9},
pages = {1-14},
keywords = {Camellia oleifera, drought stress, response, mechanism, comprehensive evaluation},
url = {https://www.sciopen.com/article/10.14067/j.cnki.1673-923x.2023.09.001},
doi = {10.14067/j.cnki.1673-923x.2023.09.001},
abstract = {ObjectiveThe drought resistance of different Camellia oleifera varieties at the seedling stage and their responses to drought stress were studied. The indexes suitable for the drought resistance evaluation and identification of Camellia oleifera were screened, and its drought resistance was comprehensively evaluated, in order to provide a theoretical basis and methods for the breeding of drought-resistant varieties of Camellia oleifera.Method28 indexes such as morphology, growth, physiology and biochemistry of different Camellia oleifera varieties under drought stress were determined to study the drought resistance of different Camellia oleifera varieties. Principal component analysis was used to screen out the evaluation or identification indexes suitable for the drought resistance of Camellia oleifera. The drought resistance of Camellia oleifera varieties was comprehensively evaluated by subordinate function value analysis. According to the change of drought resistance coefficients of each index under different drought stress intensities, the response of different Camellia oleifera varieties to drought stress was studied and the drought resistance mechanism was discussed.ResultThe results of the principal component analysis showed that 28 indexes related to drought resistance of Camellia oleifera were summarized into 3 principal components, and the cumulative contribution rate was 100%, which had strong information representation. The first principal component can be summarized as photosynthetic parameters and leaf anatomical parameters, the second principal component can be summarized as growth indexes, and the third principal component can be summarized as stomatal aperture and proline content. The corresponding drought resistance identification indicators were Pn, Gs, Tr, leaf thickness, upper epidermis thickness of leaves, stomatal aperture, stomatal density, dry matter accumulation, plant height growth and proline content. The drought resistance of 4 Camellia oleifera varieties was comprehensively evaluated by subordinate function value analysis, and the order of their drought resistance was Wu2 > Gan190 > Xing46 > Wu12. According to the changes in drought resistance coefficients of different Camellia oleifera varieties under 3 drought treatments, the responses of different Camellia oleifera varieties to drought stress were similar and had their own characteristics. Under drought stress, each Camellia oleifera variety mainly increased the number of lateral roots to improve the water absorption capacity of roots, and enhanced the resistance of plants by increasing the root-shoot ratio and root-to-plant ratio. The water loss was reduced and water use efficiency was improved by increasing leaf compactness, grid-sea ratio, stomatal density and WUE. By increasing the content of antioxidant SOD, the superoxide anion and other harmful substances could be removed to protect cell structures. By increasing the contents of soluble sugar, soluble protein and proline in leaves, the osmotic potential was reduced to regulate osmotic balance and reduce the damage of osmotic stress to plants. By increasing the contents of endogenous hormones such as ABA and MeJA, the drought resistance of Camellia oleifera was enhanced and the damage caused by drought stress was alleviated.ConclusionPn, Gs, Tr, leaf thickness, leaf epidermis thickness, stomatal aperture, stomatal density, dry matter accumulation, plant height growth and leaf proline content can be used as drought resistance identification indexes of Camellia oleifera seedlings. By the comprehensive evaluation of drought resistance, Wu2 has the strongest drought resistance. The response of different Camellia oleifera varieties to drought stress is a multi-way joint response and drought resistance mechanism, which shows both similarities and characteristics. The response of each variety under mild drought stress is different, but under severe drought stress, it is a multi-way joint response mechanism mainly dominated by SOD or ABA.}
}