十种荒漠植物种子萌发对温度的响应

Germination response to temperature of ten desert plant species

温度是影响植物种子萌发和出苗最重要的环境因子之一,研究植物种子萌发对温度的响应,对确定物种的适宜播种时期和预测田间出苗率等有着重要的意义。以10种荒漠植物:沙冬青、白沙蒿、沙打旺、中间锦鸡儿、柠条锦鸡儿、无芒隐子草、梭梭、杨柴、花棒和霸王种子为材料,在5~40℃范围设置了8个温度条件,测定种子萌发的动态变化,通过积温模型分析了供试植物种子萌发的温度三基点:萌发的基础温度(Tb)、适宜温度(To)、最高温度(Tc)以及萌发的温度时间值(θT)。结果表明:在参试物种阈值中,To以无芒隐子草最高,为33.7℃,其次是沙冬青为28.3℃,其他物种在17.4~24.9℃;Tb以沙打旺最低,为0.3℃,其次是梭梭为1.9℃,其他物种介于6.7~15.0℃;Tc以梭梭最高,为45.3℃,其次是无芒隐子草为43.9℃、沙打旺43.3℃、沙冬青39.7℃,其余物种在25.0~34.2℃;梭梭萌发温度范围最大,为1.9~45.3℃,而霸王最小,为15.0~30.0℃。供试物种在亚适温条件下,种子萌发的温度时间值从小到大依次为:沙冬青(79℃·d)、梭梭(94℃·d)、白沙蒿(114℃·d)、杨柴(127℃·d)、霸王(132℃·d)、花棒(177℃·d)、沙打旺(184℃·d)、中间锦鸡儿(217℃·d)、柠条锦鸡儿(302℃·d)、无芒隐子草(334℃·d)。

Temperature is considered one of the most important environmental factors governing seed germination and seedling emergence.Therefore,knowledge of the seed germination response to temperature has is an important criterion when determining the appropriate planting time and predicting the seedling emergence of species in the field.Seeds of Ammopiptanthus mongolicus,Artemisia sphaerocephala,Astragalus adsurgens,Caragana intermedia,Caragana korshinskii,Cleistogenes songorica,Haloxylon ammodendron,Hedysarum fruticosum,Hedysarum scoparium and Zygophyllum xanthoxylum,were used in this study.The dynamics of seed germination were determined over a range of constant temperatures from 5 to 40℃ at 5℃ intervals.The temperature thresholds(Tb,To,Tc,θT)of ten desert plant species were calculated according to the thermal time model.The results showed that:in the test species,the optimum temperature(To)was 33.7℃ for C.songorica,28.3℃ for A.mongolicus and for other species ranged from 17.4 to 24.9℃.The base temperature was 0.3℃ for A.adsurgens,followed by H.ammodendron at 1.9℃,with other species ranging between 6.7 and 15.0℃.The ceiling temperature was 45.3℃ for H.ammodendron,with C.songorica being 43.9℃,A.adsurgens 43.3℃,A.mongolicus 39.7℃,and the other species ranging from 25.0 to 34.2℃.The largest germination temperature ranges were 1.9 to 45.3℃ for H.ammodendron and 15.0 to 30.0℃ for Z.xanthoxylum.The thermal time requirement for germination,from lowest to highest,was:A.mongolicus(79℃·d),H.ammodendron(94℃·d),A.sphaerocephala(114℃·d),H.fruticosum(127℃·d),Z.xanthoxylum(132℃·d),H.scoparium(177℃·d),A.adsurgens(184℃·d),C.intermedia(217℃·d),C.korshinskii(302℃·d),C.songorica(334℃·d).