XINING, June 3 (Xinhua) -- A new study by Chinese scientists reveals how different flowering plant groups have evolved different reproductive strategies in response to seasonal droughts on the Qinghai-Tibet Plateau.

The study -- conducted by researchers at the Northwest Institute of Plateau Biology (NWIPB) of the Chinese Academy of Sciences in collaboration with colleagues at the East China Normal University -- explored the effects of spring, summer and whole growing season drought on the reproductive strategies of early-spring flowering and mid-summer flowering alpine plants on the plateau.

Their findings, published in the Journal of Plant Ecology, offer a way of predicting how alpine ecosystems will respond to future droughts.

Climate change has been intensifying seasonal droughts in alpine meadows on the Qinghai-Tibet Plateau, affecting the plants' adaptive capacity. Scientists had been curious about how plant groups with different flowering times, adjusted their reproductive allocation strategies by altering their functional traits, according to Zhang Zhenhua, a researcher at the NWIPB.

Based on in-situ sample plots on the plateau, researchers collected and analyzed observation data, including plant biomass allocation and leaf functional traits, such as specific leaf area, leaf dry matter content and leaf stoichiometric characteristics.

The study found that spring drought significantly reduced the reproductive efficiency of mid-summer flowering plants, whereas summer drought resulted in higher reproductive efficiency compared to spring drought. Early-spring flowering plants exhibited greater resilience than mid-summer flowering plants across all seasonal drought treatments, highlighting the advantage of their drought-avoidance strategy.

Under whole growing season drought conditions, early-spring flowering plants adopted a conservative resource-use strategy, including reducing specific leaf area and increasing leaf carbon-to-nitrogen ratio, carbon-to-phosphorus ratio, and leaf dry matter content, showed the study.

In contrast, mid-summer flowering plants exhibited greater morphological plasticity, showing inter-annual cumulative increases in leaf dry matter content and inter-annual cumulative decreases in specific leaf area.

"Through further analysis, we found that plateau plants have developed more subtle 'personalized' strategies to cope with droughts," Zhang said.

Early-spring flowering plants increased their flower allocation by enhancing phosphorus availability and carbon-to-nitrogen ratios, forming a nutrient-sensitive strategy. As for mid-summer flowering plants, they primarily regulated flower allocation directly by altering leaf nitrogen content and indirectly by reducing plant height to affect resource re-allocation, forming a morphological integration strategy, the study results showed.

"Our new study unveiled the co-variation patterns between functional traits and reproductive allocation in early-flowering and mid-flowering plants under seasonal drought conditions. It provides a theoretical basis for predicting how alpine ecosystems will respond to future droughts," Zhang said.