The Effect of Climatic Factors on Leaf Traits of a Non-Leguminous Nitrogen Fixing Species Hippophae tibetana (Schlecht.)?Along the Altitudinal Gradient in the Eastern Tibetan Plateau, China

摘要

Plant leaf traits and their changes along environmental gradients, reflect their environmental adaptability.Few studies have examined the relationship between the intraspecific leaf-trait and the climate on the TibetanPlateau. We determined the leaf traits of Hippophae tibetana Schlecht., a non-legume species with symbioticN fixation (SNF), at 25 sites on the Tibetan Plateau and explored the relationship between leaf traits and thelocal climate. These leaf traits included leaf length/leaf width ratio (LL/LW), leaf mass per area (LMA), leafnitrogen (N), phosphorus (P) and potassium (K) concentrations. We found that (i) N was negatively relatedto LMA, leaf nitrogen, P, and K were positively correlated with each other and the leaf LL/LW ratio waspositively related to leaf P; (ii) leaf N and P increased, while N:P ratio and LMA decreased with the increasein annual mean temperature (MAT), and the Leaf K and LL/LW increased with increasing annual meanprecipitation (MAP). Our results showed that the leaf traits of H. tibetana on the Tibetan Plateau can bemodified by the climate, and factors on Tibetan Plateau can exert a strong evolutionary pressure on leaftraits at the intra-specific levels. Out of our expectation, the growth of H. tibetana can be limited by P and K.