干旱和涝渍胁迫对入侵物种喜旱莲子草生长的影响

EfectsofDroughtandWaterlogingStresonGrowthofInvasive SpeciesAlternantheraphiloxeroides

摘要:

摘 要：喜旱莲子草作为 一种广泛入侵中国的恶性杂草,其分布主要受温度和降水的影响 。为 了 明确喜旱莲子草在不同 水分胁迫程度下的存活率、生物量及形态特征的差异,本试验在避雨条件下采用盆栽控水法对喜旱莲子草进行干旱和涝渍 胁迫处理 。结果表明:①干旱和涝渍胁迫可使植株存活率随时间呈线性下降趋势(R2 >0.9),且除高涝渍胁迫下植株死亡 速率会因环境中水量的增加而有所减缓外,植株死亡速率均会随胁迫程度升高而增大 。②干旱和涝渍胁迫可显著降低喜 旱莲子草的存活率和生物量,低干旱胁迫下植株的存活率和生物量只有 31.25%和 47.80%,干旱胁迫程度进 一 步上升就 会导致植株死亡:涝渍胁迫下植株存活率可达到 50.00%~87.50%,生物量最大降幅只有 24.68%,且最终会随着环境中 水量增加而呈升高趋势 。③低干旱胁迫只增加了 4.76%的植株分枝数,但显著降低了其它形态指标(分枝长、节间数、叶面 积):涝渍胁迫下植株除叶面积会随着环境中水量的增加呈现持续上升趋势外,其他形态指标(分枝长、分枝数、节间数)均 未受到显著影响 。 以上结果表明干旱程度才是决定喜旱莲子草存活和地理分布的主要因素,且在低度和中度干旱胁迫之 间存在该草的分布预测、防控预警和水分控制防治阅值。

Abstract:

Abstract: Asamalignantinvasiveplant,AlternantheraphiloxeroidesiswidelyinvadedinChina.Itsdistributionismainly afectedbyprecipitationandtemperature.Inordertoinvestigatethediferenceofsurvivalrate,biomasandmorphologi- calcharacteristicsofA.philoxeroidesunderwaterstresforitsdistributionprediction,preventionandcontrolofearly warning.Inthisexperiment,thedrought(low,medium andhigh)andwaterloging(low,medium anddry)streswere treatedbypotedwatercontrolmethodinrainproofenvironment.Theresultsshowedthat:①thesurvivalrateofplants decreasedlinearlywithtimeunderdroughtandwaterlogingstres(R2 > 0.9).Theplantdeathrateaddedwiththein- creaseofstreslevel,exceptthattheplantdeathratesloweddownwiththeincreaseofwaterintheenvironmentunder highwaterlogingstres.②DroughtandwaterlogingstressignificantlyreducedthesurvivalrateandbiomasofA.phi- loxeroides.Thesurvivalrateandbiomasoftheplantunderlowdroughtstreswereonly3l.25% and47.80% .Thefurther increaseofdroughtstreswouldleadtoplantdeath.However,underwaterlogingstres,thesurvivalrateofplantscan reach50.00% ~ 87.50% .Themaximumdecreaseofbiomaswasonly24.68%,andeventualyincreasedwiththeincreas- ingofwaterintheenvironment.③Lowdroughtstresonlyincreasedbranchnumberby4.76% ofA.philoxeroides,but significantlydecreasedothermorphologicalindexes(branchlength,internodenumberandleafarea).Theplantmorpholo- gyindexes(branchlength,branchnumberandinternodenumber)werenotsignificantlyafectedunderwaterlogingstres exceptleafareawhichshowedacontinuousupwardtrendwiththeincreaseofwaterintheenvironment.Theseresultsin- dicatedthatdroughtdegrewasthemainfactordeterminingthesurvivalandgeographicaldistributionoftheplant.The distributionprediction9preventionandcontrolearlywarning9watercontrolthresholdofthisplantexistedbetwenlowand moderatedroughtstres