摘要
甘草(Glycyrrhiza uralensis)为豆科甘草属多年生草本植物,具有极高的药用价值,是我国干旱、半干旱地区重要的经济和生态作物。土壤水分是限制甘草生长的主要环境因素之一,研究其抗旱适应性表现对甘草资源可持续利用具有重要意义。本研究采用聚乙二醇6000(PEG-6000)模拟干旱胁迫,研究胀果甘草(G.inflata)和乌拉尔甘草(G.uralensis)幼苗的光合特性和根系吸水能力对干旱胁迫的响应。结果表明:干旱胁迫7 d后胀果甘草和乌拉尔甘草幼苗地上部干重和根系干重均显著降低,其中地上部干重分别降低56.10%、62.50%,地下部干重分别降低16.67%和28.57%,而根冠比均有所增加。干旱胁迫均造成了胀果甘草和乌拉尔甘草幼苗叶片净光合速率(P_(n))、蒸腾速率(T_(r))和气孔导度(G_(s))的降低,与对照相比,其下降幅度分别为41.73%、67.22%,62.21%、75.38%,66.02%、82.60%。干旱胁迫下甘草幼苗荧光特性也被显著抑制(P<0.05),其中胀果甘草幼苗的光系统Ⅱ潜在活性(F_(v)/F_(o))和最大光能转换效率(F_(v)/F_(m))与对照相比分别降低21.94%和9.09%,乌拉尔甘草幼苗的F_(v)/F_(o)和F_(v)/F_(m)与对照相比分别降低35.10%和10.39%;胀果甘草和乌拉尔甘草幼苗的光化学淬灭系数(qP)在15%PEG胁迫下分别降低17.65%和27.27%。干旱胁迫降低了两种甘草幼苗叶片相对含水量和叶水势,其中胀果甘草幼苗叶片相对含水量降低11.07%,叶水势降低19.54%;乌拉尔甘草幼苗叶片相对含水量降低13.91%,叶水势降低62.56%。干旱胁迫抑制了两种甘草的根系生长,根表面积和根体积减少但增加了总根长,其中胀果甘草根系显著小于乌拉尔甘草,但胀果甘草干旱胁迫下整株根系水力学导度降幅小于乌拉尔甘草。说明在受到干旱胁迫时,胀果甘草可以保持较高的光合作用优势,同时其根系较小具有更高的根系效率,通过更强的根系吸水能力提高了作物水分利用效率,具有更强的抗旱能力。本研究可为补充完善甘草耐旱性理论提供依据,并为人工栽培及旱生植物资源保护与利用提供策略。
Glycyrrhiza uralensis is a perennial herb in the legume family.G.uralensis has high medicinal value and is an important economic and ecological crop in arid and semi-arid areas.Soil moisture is one of the main environmental factors limiting the growth of G.uralensis.Studying its drought resistance adaptability is essential for the sustainable use of licorice resources.In this study,polyethylene glycol 6000(PEG-6000)was used to simulate drought stress,and the photosynthetic characteristics and root water absorption capacity of G.inflata and G.uralensis seedlings were examined.After seven days of drought stress,the shoot dry weight and root dry weight of G.inflata and G.uralensis seedlings decreased significantly.The shoot dry weight of each tested variety decreased by 56.10%and 62.50%,respectively.The root dry weight decreased by 16.67%and 28.57%,respectively.Moreover,the root shoot ratio increased.Drought stress decreased the net photosynthetic rate(P_(n)),transpiration rate(T_(r)),and stomatal conductance(G_(s))of G.inflata and G.uralensis seedlings.Compared to the control,the decrease was 41.73%,67.22%,62.21%,75.38%,66.02%,and 82.60%.The fluorescence characteristics of G.uralensis seedlings were also significantly inhibited under drought stress.When compared to the control,the potential activity of photosystemⅡ(F_(v)/F_(o))and maximal photochemical efficiency(F_(v)/F_(m))of G.inflata seedlings decreased by 21.94%and 9.09%,respectively.When compared to the control,the F_(v)/F_(o) and F_(v)/F_(m) of G.uralensis seedlings decreased by 35.10%and 10.39%,respectively.The photochemical quenching coefficient(qP)of G.inflata and G.uralensis seedlings decreased by 17.65%and 27.27%under 15%PEG stress,respectively.Drought stress reduced the relative water content and leaf water potential of the two G.uralensis seedlings.The relative water content of the leaves of G.inflata seedlings decreased by 11.07%and the leaf water potential decreased by 19.54%.The relative water content of leaves of G.uralensis seedlings decreased by 13.91%,and the leaf water potential decreased by 62.56%.Drought stress inhibited root growth and decreased the root surface area and volume but increased the total root length in both G.uralensis species.The root of G.inflata was significantly smaller than that of G.uralensis.However,the hydraulic conductivity of the whole root of G.inflata decreased less than that of G.uralensis under drought stress.The findings demonstrate that G.inflata can have higher photosynthetic advantages during drought stress.Its smaller roots have higher root efficiency,which enhances agricultural water use efficiency through stronger root water absorption capacity and stronger drought resistance.This research can provide a basis for supplementing and improving the drought tolerance of G.uralensis and provide strategies for artificial cultivation,protection,and use of xerophyte resources.
作者
常乐乐
范子晗
梁昊枫
李哲
张岁岐
李玉萍
CHANG Lele;FAN Zihan;LIANG Haofeng;LI Zhe;ZHANG Suiqi;LI Yuping(State Key laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University,Yangling 712100,Shaanxi,China;College of Resources and Environment,Northwest A&F University,Yangling 712100,Shaanxi,China;Guangdong Provincial Key Laboratory of Applied Botany,South China Botanical Garden,Chinese Academy of Sciences,Guangzhou 510650,Guangdong,China)
出处
《草业科学》
CAS
CSCD
北大核心
2024年第2期382-393,共12页
Pratacultural Science
基金
广州市科技计划项目“胀果甘草bHLH转录因子GibHLH2调控甘草酸积累的机制研究(202201010756)”
广东省基础与应用基础研究基金委员会-区域联合基金-青年基金项目(2021A1515110122)。
关键词
甘草
干旱胁迫
光合特性
根系水力学导度
抗旱性
Glycyrrhiza uralensis
drought stress
photosynthetic characteristics
root hydraulic conductivity
drought resistance
