Assessment of the Reproductive Potential of Hierochloe odorata (L.) Beauv. and H. repens (Host) Beauv. (Poaceae) at Different Levels of Organization

Abstract

The results of a study of the dynamics of elements of seed productivity amphimict Hierochloe repens (Host) Beauv. (2n = 28) and the optional apomict Hierochloe odorata (L.) Beauv. (2n = 42) (Poaceae) are presented. The plants were grown in the absence of competition and in single-species artificial cenoses with low (5 plants/m2) and high (20 plants/m2) starting density. It is found that, according to the classification of ecological strategies, the plants are K-species and the expenses of reproduction are 1.8–5.8% of the biomass of a specimen. The reproductive capacity of 2-year cenoses depend on the starting density of plants. In low-density cenoses, plants have 2.4–2.7 times fewer generative shoots when compared to high-density cenoses. The influence of species features (F1) on fruiting abundance varies with age. At 2-year coenosis, the share of the influence of this factor on the number of generative shoots per unit area is 43.11% (F1 = 16.12%), at 3-year coenosis 60.04% (F1 = 31.26%), and at 4-year coenosis 29.19% (F1 = 7.24%; F05 = 4.49; F01 = 8.53). The intrapopulation correlation of reproduction indices with the dimension indices of specimens, expressed through the weight and share of organ weight from the biomass of specimens, is clarified. The real seed productivity of H. repens plants was 2.2 times higher in specimens and 1.4 times higher in cenoses compared to H. odorata. Reproductive imbalance in H. odorata was associated with polyploidy and the possibility of apomixis.