摘要
【目的】研究不同油茶品种苗期的抗旱性及其对干旱胁迫的响应,筛选出适用于油茶抗旱性评价或鉴定的指标,并对其抗旱性进行综合评价,以期为油茶抗旱品种的选育等提供理论依据和方法。【方法】测定不同油茶品种在干旱胁迫下的形态、生长、生理生化等28项指标,研究不同油茶品种的抗旱性,运用主成分分析法筛选出适用于油茶抗旱性大小的评价或鉴定指标,并利用隶属函数法对油茶品种的抗旱性进行综合评价,根据不同干旱胁迫强度下各指标抗旱系数的变化情况,研究不同油茶品种对干旱胁迫的响应并探讨其抗旱机制。【结果】主成分分析结果得出,将与油茶抗旱性相关的28项指标归纳成3个主成分,累计贡献率为100%,具有很强的信息代表性;第一主成分可概括为光合参数和叶片解剖参数,第二主成分可概括为生长指标,第三主成分可概括为叶片气孔开度和脯氨酸含量,对应的抗旱性鉴定指标分别为净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、叶片厚度、叶片上表皮厚度、气孔开度、气孔密度、干物质积累量、株高生长量及叶片脯氨酸含量。运用隶属函数值分析法对4个油茶品种的抗旱性进行综合评价,抗旱性强弱顺序为无2>赣190>兴46>无12。根据不同油茶品种在3个干旱胁迫强度下抗旱系数的变化情况得出,各油茶品种对干旱胁迫的响应既有相似之处又各有特点。干旱胁迫下,各油茶品种主要通过增加侧根数来提高根系的吸水能力,通过提高根冠比和根占整株比来增强植株的抗性;通过提高叶片紧实度、栅海比、气孔密度及水分利用效率(WUE)来减少水分散失和提高水分利用效率;通过提高抗氧化物质SOD的含量来清除超氧根阴离子等有害物质,保护细胞结构;通过提高叶片中可溶性糖、可溶性蛋白、脯氨酸等含量来降低渗透势,调节渗透平衡,减轻渗透胁迫对植物的伤害;通过增加内源激素ABA和MeJA含量来增强油茶的抗旱性,缓解干旱胁迫对油茶造成的伤害。【结论】净光合速率、气孔导度、蒸腾速率、叶片厚度、叶片上表皮厚度、气孔开度、气孔密度、干物质积累量、株高生长量及叶片脯氨酸含量可作为油茶苗期的抗旱性鉴定指标;经抗旱性综合评价,无2的抗旱性最强;不同油茶品种对干旱胁迫是多途径的联合响应及抗旱机制,既有相同之处又各有特点,各品种在轻度干旱胁迫下的响应区别较大,但在重度干旱胁迫下主要是以SOD或ABA为主导的多途径响应及抗旱机制。
【Objective】The 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.【Method】28 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.【Result】The 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.【Conclusion】Pn,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.
作者
何小三
周文才
邱凤英
龚春
徐林初
肖相元
王玉娟
HE Xiaosan;ZHOU Wencai;QIU Fengying;GONG Chun;XU Linchu;XIAO Xiangyuan;WANG Yujuan(Jiangxi Academy of Forestry,Nanchang 330032,Jiangxi,China;Key Laboratory of Germplasm Resources Protection and Utilization of Camellia oleifera in Jiangxi Province,Nanchang 330032,Jiangxi,China)
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2023年第9期1-14,共14页
Journal of Central South University of Forestry & Technology
基金
江西省重点研发计划项目(20203BBFL63056)
中央财政林业科技推广示范项目(JXTG〔2021〕22号)。
关键词
油茶
干旱胁迫
响应
机制
综合评价
Camellia oleifera
drought stress
response
mechanism
comprehensive evaluation
