干旱胁迫对3种灌木不同器官化学计量特征的影响

采用盆栽控水试验,研究了3个水分处理,即田间持水量(FC)的(75±5)％、(55±5)％和(35±5)％,对丁香、黄刺梅、连翘的叶、茎、极细根(0～1 mm)、细根(1～2 mm)和粗根(＞2 mm)化学计量特征的影响.结果表明:3种灌木相同器官间氮(N)和磷(P)含量以及C∶N、C∶P、N∶P均存在显著差异.随着干...

Effects of drought stress on the stoichiometric characteristics in different organs of three shrub species

In order to explore how water stress affects the stoichiometric characteristics in leaves,stems,very fine roots(0-1 mm),fine roots(1-2 mm)and thick roots(>2 mm)of three shrub species,we studied the effects of three water treatments(75±5)%,(55±5)%and(35±5)%of field water capacity(FC)]on the stoichiometric characteristics of different organs of Syringa oblata,Rosa xanthina and Forsythia suspensa in a pot experiment.The results showed that there were significant differences in nitrogen(N)and phosphorus(P)contents,C:N,C:P and N:P of the same organ among the three species.With the intensification of drought stress,there was no significant change of C content in all organs of the three species.The N content increased in leaves,but decreased gradually in stems.The N content in very fine roots and fine roots increased first and then decreased.The P content decreased in leaves and stems,while increased first and then decreased in very fine roots and fine roots.Under drought stress,leaf C:N decreased,C:P and N:P of leaf and stem increased.There was the strongest effect of drought stress on the C:N of very fine roots and C:P and N:P of leaves.There was the least effect of drought stress on C:N,N:P of thick roots and C:P of very fine roots.There was no significant correlation between the contents of C,N in soil and the contents of C,N and P in shrub organs,but soil P content was significantly correlated with the contents of C,N and P in leaves and roots.It was concluded that the relative P limitation in soil was the most important factor affecting the stoichiometric characteristics of shrub organs.Drought had different effects on the stoichiometry of different organs in different shrub species.The stoichio-metry of leaves and very fine roots was more sensitive to drought stress than that of other organs.Drought might affect the stoichiometric characteristics especially related to P in different organs of shrubs,mainly by affecting plant absorption of soil P and its distribution in different organs.