Comparison of sexual reproductive characteristics of Leymus chinensis populations in two habitats of the Songnen Plain, China

Sexual reproduction plays an important role in the reproductive strategies of clonal grasses. Changes in external habitat conditions and the number of modules can directly or indirectly affect the sexual reproduction of clonal grasses. In this study, the quantitative characteristics, biomass accumulation and allocation, and sexual reproductive characteristics of Leymus chinensis reproductive ramets with different leaf numbers were analyzed in enclosure meadows and abandoned farmland. The results showed that: 1) the total ramet density, reproductive ramet density, and heading rate of L. chinensis populations in the abandoned farmland were significantly higher than those in the enclosure meadow (P < 0.05), whereas the proportion of vegetative ramets in the enclosure meadow was significantly higher than that in the abandoned farmland. L. chinensis with multiple reproductive ramets and a high heading rate in the abandoned farmland had the potential to produce more seeds, while L. chinensis in the enclosure meadows was more inclined to propagate vegetatively. 2) Stem biomass, leaf biomass, total biomass, and leaf biomass allocation were significantly higher in reproductive ramets with more leaves than in those with fewer leaves in the enclosure meadows. Leaf, inflorescence, and total biomass were significantly higher in reproductive ramets with fewer leaves in abandoned farmland than in the enclosure meadows. The presence of multileaf reproductive ramets of L. chinensis was not universally beneficial across habitats. 3) Leaf biomass allocation, stem biomass allocation, inflorescence biomass allocation, reproductive allocation Ⅰ, reproductive allocation Ⅱ, and reproductive reallocation in L. chinensis reproductive ramets were significantly higher in the abandoned farmland than in the enclosure meadows. Sexual reproductive characteristics, such as reproductive ramet height, inflorescence length, seed number, seed biomass, 100-seed weight, and seed-setting rate, were significantly higher in abandoned farmlands than in enclosure meadows. Compared with the enclosure meadows, the seeds of L. chinensis had a quantitative advantage in abandoned farmlands, with more resources devoted to effective seed production. Our study found that the sexual reproductive characteristics and resource allocation strategies of reproductive ramets of L. chinensis with different leaf numbers exhibited strong plasticity across the two habitats.