Arid Zone Research ›› 2022, Vol. 39 ›› Issue (6): 1875-1884.doi: 10.13866/j.azr.2022.06.18

• Plant Ecology • Previous Articles     Next Articles

Responses of seed germination of Caragana korshinskii to different temperatures and soil water content

YANG Hui(),ZHANG Ze,ZHANG Lan,YAN Xingfu()   

  1. College of Biological Science and Engineering, North Minzu University/Laboratory of Ecological Protection of Agro-pastoral Ecotones in the Yellow River Basin, Yinchuan 750021, Ningxia, China
  • Received:2022-06-09 Revised:2022-09-02 Online:2022-11-15 Published:2023-01-17
  • Contact: Xingfu YAN E-mail:2786707811@qq.com;xxffyan@126.com

Abstract:

Caragana korshinskii is a xeromorphic shrub of Fabaceae distributed in the sandy grasslands of the desert or semi-arid areas in Northwest China, and one of the main shrub species applied widely in the practice of water, soil conservation, wind-break, and sand-fixation. In this paper, different soil water contents (4%, 8%, 12%, 16%, 20%, and 30%) were conducted to investigate the responses of the seed germination of C. korshinskii to different temperatures and soil water content under six constant temperatures (5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, and 30 ℃) controlled using artificial climate incubators. The results showed that: Temperature, soil water content, and their interaction all significantly impacted the germination percentage (GP), germination rate (GR), germination index (GI), and vigor index (VI) of C. korshinskii seeds. Seeds exposed to 10 ℃ had the highest GP of 87.5%, and those to temperatures of 15 ℃, 20 ℃, and 25 ℃ had high GP as well. Then, it substantially declined when the cultivation temperature elevated to 30 ℃. GR, GI, and VI were all minimized at 5 ℃, and they all increased first and declined with elevated temperature, and maximized at 25 ℃ or 15 ℃. With the soil water content elevating, trends of increasing and decreasing were all detected in GP, GI, and VI at all temperatures. The maxima of the above three parameters were observed at 30% soil water content under 5 ℃ while they were detected at 20% or 16% soil water content under other temperatures. With increased soil water content, the GR of seeds cultivated at 5 ℃ increased gradually. However, those of seeds cultivated at other temperatures increased first and then declined. It maximized in 20% soil water content at the temperatures of 10 ℃, 15 ℃, and 20 ℃, while in 16% soil water content at the temperatures of 25 ℃ and 30 ℃. The inhibition effects of higher temperature and soil water content on the germination of C. korshinskii seeds during the summer and autumn may be a protective strategy to ensure some seeds enter soil seed bank and reduce the risk of seedling mortality. Also, the C. korshinskii seeds could germinate at relatively lower temperatures and soil water content during early spring, which may compensate for the above inhibition effects of higher temperature and soil water content on seed germination.

Key words: Caragana korshinskii, temperature, soil water content, seed germination, seedling regeneration