模拟氮沉降对四川马先蒿(原亚种)花特征及表型选择的影响  

Effects of simulated nitrogen deposition on flower characteristics and phenotypic selection of Pedicularis szetschuania subsp.szetschuanica

作　　者：田思琪 路宁娜[1] 赵志刚 王红梅 TIAN Si-qi;LU Ning-na;ZHAO Zhi-gang;WANG Hong-mei(School of Life Sciences,Northwest Normal University,Lanzhou 730070,China;State Key Laboratory of Grassland and Agro-ecosystems,School of Life Sciences,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]西北师范大学生命科学学院,兰州730070 [2]兰州大学生命科学学院草地农业生态系统国家重点实验室,兰州730000

出　　处：《兰州大学学报（自然科学版）》2022年第2期270-274,共5页Journal of Lanzhou University(Natural Sciences)

基　　金：国家重点研发计划项目(2017YFC0504801);国家自然科学基金项目(31660110);甘肃省重点研发计划项目(18YF1FA053)。

摘　　要：以青藏高原高寒草甸的四川马先蒿(原亚种)为研究材料,长期施肥模拟氮沉降,分析氮沉降对花表型选择的影响.连续施肥 NH_(4)NO_(3)(5 g/m^(2)) 5 a 后,于盛花期测定花特征,观察访花频率,分批收集种子,采用线性回归模型对雌性适合度进行表型选择分析.结果显示,氮添加处理组,四川马先蒿(原亚种)株高变高,叶长变短,种子产量增加;氮添加处理减弱了花大小、访花频率与其他特征的相关性;对照处理中株高、叶长、花数目和花大小有显著的选择差,氮添加处理中花大小无显著选择差,氮添加改变了对花大小总的选择压力,两组处理中,花数目均有显著的选择梯度,但氮添加处理降低了对花数目的选择强度,两组处理中对花蜜量的表型选择均不显著.氮添加导致对花大小的表型选择减弱,可能是因为氮添加处理增加了种子的产量,即增加了种群平均适合度,削弱对植物特征的选择强度,从而降低对植物特征选择机会.因此氮添加可以通过增加种群平均适合度改变对植物特征的表型选择.With Pedicularis szetschuania subsp.szetschuanica from alpine meadows on the Qinghai-Tibetan Plateau as the research material,nitrogen deposition was simulated by long-term fertilization and the effect of nitrogen deposition on flower phenotypic selection analyzed.A 5-year continuous application of NH_(4)NO_(3)was conducted to simulate nitrogen deposition,with the floral traits measured,the pollinator behavior observed and the phenotypic selection of female fitness components analyzed using the linear regression model.The results showed that the plants after nitrogen addition were higher with shorter leaves and yielded more seeds.Nitrogen addition weakened the correlations between flower size,pollinator visiting frequency and other characteristics.Significant differences in the selection for plant height,leaf length,flower number and flower size were detected in control treatment,while no significant difference in selection for flower size was detected in nitrogen addition treatment.Nitrogen addition changed the total selection pressure on flower size in both treatments.In nitrogen addition treatment the selection intensity of flower number reduced.The phenotypic selection for nectar amount did not differ between the two treatments.Nitrogen addition reduced the phenotypic selection of flower size,which might be due to the increase of seed yield,that is,the mean fitness of the population.Increasing the mean fitness of the population would weaken the intensity of plant feature selection,thus reducing the chance of plant feature selection.Nitrogen addition could change the phenotypic selection of plant characteristics by increasing the mean fitness of the population.

关 键 词：四川马先蒿 氮沉降 表型选择 雌性适合度 

分 类 号：Q944.3[生物学—植物学]