不同温度盐爪爪种子发芽特性和幼苗期耐旱性

Drought tolerance during seed germination and young seedling period of Kalidium foliatum under different temperatures

当前干旱区荒漠植物盐爪爪(Kalidium foliatum)种群存在自我更新障碍,荒漠区很少见到幼苗,水分和温度可能是荒漠区造成自我更新障碍的两个主要的生态因素。本研究采用聚乙二醇(PEG-6000)模拟干旱,在不同温度下(20℃/5℃、25℃/10℃、30℃/15℃和35℃/20℃),研究干旱胁迫(0、5%、10%、15%、20%、30%PEG)对盐爪爪种子发芽特征和幼苗生长的影响,旨在探索盐爪爪种子发芽和幼苗生长与其原生境温度和干旱条件的相关性。结果表明:不同温度对盐爪爪种子萌发和幼苗生长有显著影响(P<0.01),其中发芽率、发芽指数、发芽势在30℃/15℃条件下达到最高,该温度可作为盐爪爪种子发芽特性和幼苗生长时期最适宜的温度;不同浓度的PEG-6000溶液对其种子萌发产生显著影响(P<0.05),在30℃/15℃下,高浓度(>15%PEG-6000)溶液对盐爪爪种子的萌发有抑制作用,且随着浓度的增大抑制作用也随之增强,低浓度的PEG-6000溶液(5%)对盐爪爪种子的发芽率、发芽势和发芽指数略有促进作用,适当的干旱胁迫有利于盐爪爪幼苗的生长,使出苗整齐。

Currently,the regeneration of the population of eremophyte Kalidium foliatum faces obstacles,and seedlings are rarely seen in desert areas.Water and temperature may be two main ecological factors inhibiting self-renewal in arid and desert areas.Therefore,the aim of this study was to explore whether the seed germination characteristics and seedling growth are related to the temperature and drought in the original habitat of K.foliatum.The seedling growth characteristics were studied under different temperatures(20℃/5℃,25℃/10℃,30℃/15℃,35℃/20℃)and drought stress(PEG 0,5%,10%,15%,20%,25%,and 30%PEG).The results showed that different temperatures significantly affected the seed germination and seedling growth of K.foliatum(P<0.01),and the germination rate and potential of K.foliatum at 30℃/15℃were the highest.Different concentrations of PEG-6000 solution had significant effects on seed germination(P<0.05).At 30℃/15℃,a low concentration of PEG-6000 solution(5%)slightly promoted the germination rate,potential,and index of K.foliatum seeds,whereas a high concentration(>15%PEG-6000)solution inhibited the germination of K.foliatum seeds,and the inhibition increased with increased concentration.Therefore,30℃/15℃can be used as the most suitable temperature for seed germination characteristics and seedling growth period of desert plant K.foliatum.The low temperature in the original habitat in spring is the main factor limiting the self-renewal of the K.foliatum population.Appropriate drought stress is conducive to enhancing the growth of K.foliatum seedlings and promoting their emergence.