Nitrogen-influenced competition between the genders of Salix rehderiana

Abstract

Male and female willow plants show spatial segregation of genders along the environmental gradients. Skewed gender ratio of willows is not only related to altitude, but also to nutrient status and sexual competition, which can affect their growth and defense by altering secondary metabolite production. The relationship between metabolites and nutrients in the two genders of Salix rehderiana was explored in the Gongga Mountain. We found gender ratio was altered with a change in soil nitrogen (N) status; in the high N habitats, secondary metabolites accumulated in males. Furthermore, pot experiment was conducted to test the effect of nitrogen supply on gender competition in S. rehderiana. Sufficient N supply stimulated females to produce amino acids and carbon-containing secondary metabolites for maintaining their carbon-nitrogen balance, but extra nitrogen for males was used for growth to occupy more space. N supply induced foliar nutrient imbalances and growth of opportunistic species, allowing them to outcompete neighbors. Better carbon allocation and storage in male than female willows would benefit intersexual competitiveness of males if environment N increases. Competition between the genders has a significant correlation with skewed gender ratio, spatial separation and resource utilization. Female willows would suffer fiercer competition for space by males with the increased soil N, which would result in the gender ratio alteration. Therefore, gender ratio of willows is likely to convert to gender balance from female-biased with long-term N deposition in the future.

Differences in phytohormone and flavonoid metabolism explain the sex differences in responses of Salix rehderiana to drought and nitrogen deposition

“…Cuttings of S. rehderiana were collected from the Hailuogou Natural Reserve of Mount Gongga (101°30 0 to 102°15 0 E, 29°30 0 to 30°20 0 N) in Sichuan Province, China, in March 2019. The monthly average temperature ranges from À4.3 to 12.0°C, and the mean annual air temperature is 3.8°C (Song et al, 2021). The altitude of the sampling plot (102°01 0 E, 29°35 0 N) was approximately 2600 meters.…”

“…As dioecious woody plants, some Salix species exhibit sex differences in acclimation to the environment, which leads to biased sex ratios in the population (Delph, 1999; Dudley & Galen, 2007; Jiang et al., 2016; Ueno et al., 2007). In our previous studies, it was found that nutrients influence the competition between the sexes of S. rehderiana and Salix paraplesia , which exhibited sex differences in response to water deficiency and nocturnal warming (Liao et al., 2019; Liao et al., 2020; Song et al., 2021). At the transcriptional and metabolic levels, plants can modulate gene expression and metabolite levels to acclimate to abiotic stresses.…”