水分和养分添加对内蒙古荒漠草原沙生针茅生长与生理特性及其敏感性的影响

Effects of water and nutrient addition on the growth and physiology of Stipa glareosa in a desert steppe in Inner Mongolia

为了探究荒漠草原优势植物对水分和养分输入的响应特征和适应规律,通过设置2个水分水平(自然降雨、水分添加)和3个养分水平(无养分添加、N添加、NPK添加),共6个处理,研究水分与养分添加对荒漠草原优势植物沙生针茅(Stipa glareosa)生长、生理及其敏感性的影响。双因素方差分析结果表明:水分主效应、养分主效应及水分和养分的交互作用对沙生针茅的生长生理特性具有显著影响(P<0.05)。水分添加显著增加了沙生针茅的叶片鲜重、干重、株高和相对电导率,降低了SOD酶活性;养分添加增加沙生针茅的叶面积,N添加增加了丙二醛含量,NPK添加降低了叶绿素a/b(Ca/Cb)和SOD酶活性;水分和养分的交互作用对叶面积、叶片厚度、叶绿素a(Ca)、脯氨酸、蛋白质含量和SOD酶活性具有显著影响。敏感性分析表明,叶面积和Ca含量对同时添加水分和NPK处理较为敏感,而Ca/Cb对水分添加处理更为敏感。综上所述,沙生针茅可以通过改变特定的生长生理特性适应水分和养分的变化,这对于揭示荒漠草原植物对全球变化的响应机制具有重要意义。

To explore the adaptive responses of dominant species in a desert steppe to environmental changes,we tested the effects of six treatments with two water levels(natural precipitation andartificial irrigation)and three nutrient levels(no nutrient addition,N addition and NPK addition)on the growth and physiology of Stipa glareosain Inner Mongolia.The results of two-wayANOVAshowed that the main factors(water andnutrients)and water×nutrientinteraction had significant effects on some of the growth and physiological parametersof S.glareosa(P<0.05).Water supplementation significantly increased the leaf fresh weight,leaf dry weight,plant height and relative electrical conductivity but decreased superoxide dismutase(SOD)activity.Both N and NPK addition increased leaf area.N addition increased malondialdehyde content,whereasNPK addition decreased chlorophyll a/b and SOD activity.The water×nutrient interaction factor had significant effects on leaf area,leaf thickness,chlorophyll a,proline and protein contents and SOD activity.Moreover,the leaf area and chlorophyll a content of S.glareosawere more sensitive to water and NPK addition,whereas thechlorophyll a/bwas more sensitive to water addition treatments.In conclusion,our results suggest that S.glareosacould adapt to fluctuations in water and nutrient availability by changing specific growth and physiological characteristics,which is important for revealingthe response mechanism of plantsin a desert steppe to climate changes.