Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (4): 428-439.

• Research Articles •

### Effects of the first rainfall timing and amount on morphological characteristics and chlorophyll fluorescence of two ephemeral species in the Gurbantünggüt Desert, northwestern China

ZHANG Yu-Lin1,2, YIN Ben-Feng1, TAO Ye1, LI Yong-Gang1, ZHOU Xiao-Bing1,*(), ZHANG Yuan-Ming1,*()

1. 1State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
2University of Chinese Academy of Sciences, Beijing 100049, China
• Received:2020-11-23 Accepted:2021-11-24 Online:2022-04-20 Published:2021-12-13
• Contact: ZHOU Xiao-Bing,ZHANG Yuan-Ming
• About author:*(Zhou XB, zhouxb@ms.xjb.ac.cn) ;
• Supported by:
National Natural Science Foundation of China(41977099);Xinjiang Innovation Environment Project(2018Q009);Xinjiang Innovation Environment Project(2021D01E03);Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y201976)

Abstract:

Aims Early spring rainfall event is an important factor affecting the growth of desert ephemeral plants. This study aims to understand the effects of the first rainfall timing and amount on the photosynthesis and growth of desert ephemeral plants in early spring.

Methods Two dominant ephemeral species, Erodium oxyrhinchum and Centaurea pulchella were selected in the Gurbantünggüt Desert, and treatments of three times of the first rainfall (10, 20 and 30 days after the snow melted completely) and three amounts of rainfall (5, 10 and 15 mm) were conducted. The plant morphology, biomass and chlorophyll fluorescence of the two plants were determined.

Important findings When the rainfall occurred on the 10th day after the snow melted completely, the leaf area and total biomass of the E. oxyrhinchum increased significantly with the rainfall amount, while the maximum photochemical efficiency decreased. If the rainfall was applied on the 20th and 30th day after the snow melted completely, the leaf area of the E. oxyrhinchum and C. pulchellaincreased significantly with the rainfall amount. On the other hand, if the treatments were applied with the addition of 5 mm rainfall, the maximum photochemical efficiency of the E. oxyrhinchum and C. pulchella decreased firstly and then increased significantly with the delay of the first rainfall timing. If the treatments were applied with the addition of 10 mm rainfall, the shoot to root ratio (S/R), root length and total biomass of the E. oxyrhinchum increased firstly and then decreased significantly with the delay of the first rainfall timing, but the root length of the C. pulchella increased significantly. If the treatments were applied with the addition of 15 mm rainfall, the leaf area, S/R and maximum photochemical efficiency of the E. oxyrhinchum increased with the delay of the first rainfall timing. For the C. pulchella, total biomass increased significantly, maximum photochemical efficiency and S/R decreased significantly with the delay of the first rainfall timing. The root length of the E. oxyrhinchum and C. pulchella were significantly positively correlated with soil moisture content of 0-5 cm and 5-10 cm, respectively. In general, the effects of the first rainfall amount on plant growth are much larger than effects of the first rainfall timing in early spring. However, different ephemeral species showed different trends with the changes in rainfall pattern. The variation in early spring rainfall caused by climate change can affect the morphological characteristics of desert ephemeral plants in desert, and then may affect the stability of desert ecosystem in early spring.