Abstract
The decreasing precipitation with global climate warming is the main climatic condition in some sandy grassland ecosystems. The understanding of physiological responses of psammophytes in relation to warming and precipitation is a possible way to estimate the response of plant community stability to climate change. We selected Lespedeza davurica, Artemisia scoparia, and Cleistogenes squarrosa in sandy grassland to examine the effect of a combination of climate warming and decreasing precipitation on relative water content (RWC), chlorophyll, proline, and antioxidant enzyme activities. We found that all experimental treatments have influenced RWC, chlorophyll, proline, and antioxidant enzyme activities of three psammophytes. L. davurica has the highest leaf RWC among the three psammophytes. With the intensification of precipitation reduction, the decreasing amplitude of chlorophyll from three psammophytes was L. davurica > C. squarrosa > A. scoparia. At the natural temperature, the malondialdehyde (MDA) content of the three psammophytes under severe drought treatment was much higher than other treatments, and their increasing degree was as follows: A. scoparia > C. squarrosa > L. davurica. At the same precipitation gradient, the proline of three psammophytes under warming was higher than the natural temperature. The differences in superoxide dismutase (SOD) among the three psammophytes were A. scoparia > L. davurica > C. squarrosa. Moreover, at natural temperature, more than 40% of precipitation reduction was most significant. Regardless of warming or not, the catalase (CAT) activity of A. scoparia under reduced precipitation treatments was higher than natural temperature, while the response of L. davurica was opposite. Correlation analyses evidenced that warming (T) was significant in L. davurica and precipitation (W) was significant in A. scoparia and C. squarrosa according to the Monte-Carlo permutation test (p = 0.002, 0.004, and 0.004). The study is important in predicting how local plants will respond to future climate change and assessing the possible effects of climate change on sandy grassland ecosystems.
Highlights
For nearly a hundred years, the global climate has been in a state of continuous warming
The results showed that warming had a significant effect on leaf relative water content (RWC) of A. scoparia and L. davurica (p = 0.003), precipitation reduction had a distinct impact on that of L. davurica and C. squarrosa (p ≤ 0.05), and hydrothermal interaction had significant effect only on L. davurica (p = 0.008) (Figures 2A–C)
Our results showed that warming remarkably impacted the total chlorophyll content of the three psammophytes (A. scoparia, p = 0.003; L. davurica, p = 0.002; C. squarrosa, p < 0.001) (Figures 2D–F), precipitation reduction notably affected that of A. scoparia (p < 0.05) and L. davurica (p < 0.001), and hydrothermal interaction remarkably influenced that of L. davurica and C. squarrosa (p < 0.05) (Figures 2D–F)
Summary
For nearly a hundred years, the global climate has been in a state of continuous warming. The increase in temperature and the decrease in precipitation limit the growth and physiological characteristics of plants and affect the stability of plant community in sandy grassland (Luo et al, 2008; Xu et al, 2014; Chen et al, 2015). Climate warming may significantly influence plant carbon assimilation, which could alter community composition (Peng et al, 2017). From the point of view of ecology and evolution, the adjustment of adaptive strategies of dominant species in plant communities is very important to maintain vegetation stability, as they both provide effective buffers against rapid climate change and contribute to long-term adaption (Hu et al, 2020; Zuo et al, 2020)
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