Can botanists help keep a vital ally against desertification growing in the desert?

If there’s one set of plants you’d expect to benefit from a hotter and drier climate, it would be desert plants. Recent research by Zhu and colleagues, published in AoB PLANTS, examines how desert plants, specifically Haloxylon ammodendron, respond to changes in rain frequency and temperature across four deserts in Northwest China. They find that even these survivors face challenges in the future due to climate change and suggest possible strategies to ensure their continued survival.

Haloxylon ammodendron, also known as Saxoul, is a dominant desert plant species that plays a critical role in population regeneration and community succession in desert ecosystems. It’s particularly useful in fighting desertification because it is drought- and salt-tolerant. It’s a psammophyte, a plant that can grow in loose sand. For this reason, it’s also very helpful in fixing sand and preventing the spread of desert. It’s a plant you want growing in these harsh conditions, but it’s not a plant whose habitat you want to see spreading. 

Zhu and colleagues investigated the effects of different rain frequencies and temperatures on seed germination and seedling emergence in the Tengger Desert, Badain Jaran Desert, Gurbantonggut Desert, and Mutthar Desert. They collected thousands of seeds from the desert to analyse and test for germination, along with observing plants in the desert to see when they germinated.

The study’s results demonstrated that rain frequency was the determining factor for seed germination and seedling emergence in these desert regions, with the optimal rain frequency being ten times per month. As the rain frequency decreased, so did the rate of seed germination and seedling emergence. Interestingly, temperature appeared to be less of a limiting factor for seed germination in the Tengger Desert, Badain Jaran Desert, and Gurbantonggut Desert, with temperatures ranging from 10 °C to 25 °C and from 20/10 °C to 30/15 °C, respectively. However, in the Mutthar Desert, seed germination was inhibited at higher temperatures of 25 °C and 30/15 °C.

These findings suggest that Haloxylon ammodendron has developed an opportunistic germination strategy, allowing it to adapt to its harsh desert environment. However, as climate change progresses, the combination of less frequent rainfall and increased temperatures may pose significant challenges to the germination and growth of this essential desert plant species.

So, how can we ensure the survival of Haloxylon ammodendron and other desert plants in the face of climate change? The researchers propose that promoting the regeneration of Haloxylon ammodendron communities through irrigation and seedling transplant methods could provide a viable solution to this problem. Zhu and colleagues say that artificially providing the necessary water resources and creating suitable growing conditions can help desert plants adapt to new climatic conditions and maintain their vital roles in desert ecosystems. In their article, they write:

In deserts of Northwest China, the best time for seed germination of H. ammodendron is late spring and early summer, when temperature would be appropriate and sand would be moist after rainfall. Populations of H. ammodendron with larger seed mass may have an advantage in desert ecosystems, e.g. Tengger Desert and Gurbantonggut Desert. The effect of seed mass on seed germination and seedling emergence of H. ammodendron will need more research, especially under sand burial (Baskin and Baskin 2014). It is predicted that seed germination of H. ammodendron will occur earlier under global warming. However, considering both warming and less frequent rainfall, seed germination might be more difficult for H. ammodendron, especially in the Mutthar Desert. Therefore, the regeneration of the H. ammodendron community should be enhanced in the future by irrigation and seedling transplant.

Zhu et al. 2023

READ THE ARTICLE

Zhu, Y., Jia, Z., Wang, G., Ning, H., Ji, X. and Luo, Q. (2023) “Response of seed germination and seedling emergence of Haloxylon ammodendron to rain frequency and temperature change from four desert ecosystems, Northwest China,” AoB PLANTS, 15(2), p. lac048. Available at: https://doi.org/10.1093/aobpla/plac048.

Cover image: Haloxylon ammodendron, Shanshan County, Xinjiang. Anagoria / Wikimedia Commons.