ObjectiveExtremely arid oasis is a sensitive area of global change, especially water shortage and changes in hydrological processes had led to strong heterogeneity in the oasis soil environment. How plants adapt to high soil heterogeneity is a key scientific issue in the maintenance of oasis plant diversity. So investigating plant leaves, the most sensitive organ traits and their response to soil water and salt factors is helpful to reveal the fundamental strategies of plant adaptation under environmental heterogeneity conditions.
MethodIn this study, the common plant leaves of Ejina, a typical desert oasis, were selected as research objects, and eight leaf functional traits of 25 plants were selected, including leaf thickness (LT), leaf dry matter content (LDMC), specific leaf area (SLA), leaf carbon content (LCC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), leaf carbon to nitrogen ratio (C/N) and leaf nitrogen to phosphorus ratio (N/P). The correlations between functional traits and their characteristics at the community level were analyzed. And the response of leaf functional traits to different soil water and salt environments was discussed.
ResultResults showed that: (1) each leaf functional trait had varying degrees of variation, among which SLA had the highest coefficient of variation and LCC had the smallest coefficient of variation. (2) There was a significant synergy or trade-off between some functional traits. LT and SLA, LDMC and SLA, LPC and LDMC, LNC and C/N, LPC and N/P were significantly negatively correlated (P < 0.01), and there was a significant negative correlation between LCC and LT, LNC and LCC, C/N and N/P (P < 0.05). LDMC and C/N, SLA and LPC, LCC and C/N, N/P and LCC, LNC and N/P were significantly positively correlated (P < 0.01), and there was a significantly positive correlation with LDMC and LCC, SLA and LNC (P < 0.05). (3) Leaf functional traits had a certain degree of difference in response to soil water and salt factors. In the low-water and low-salt environment, the leaves were adapted to drought-stressed soil environment by increasing LDMC, LNC, N/P, and lowering LPC and C/N. In the low-water and high-salt environment, the leaves improved LNC and LPC to reduce the soil environment dominated by salt stress by reducing LDMC, C/N and N/P. In the (relative) high-water and high-salt environment, the leaves were mainly adapted to the soil environment with relatively low salt stress and relatively sufficient water content by reducing LNC, N/P and increasing C/N.
ConclusionIn the Ejina Oasis Region, the leaf functional traits of plant community adapted to the extreme arid environment through a certain degree of variation and a synergistic-balanced functional combination. The response to soil water and salt factors also had a certain degree of difference. Among them, the effect of salt content on the leaf functional traits of the plant community was more critical. This study provides a scientific basis for further research on the adaptation mechanism of oasis plants in extreme arid regions to soil water and salt factors.