Stoichiometric characteristics of Roegneria yushuensis in different growth periods

Studying the stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in plants is of great significance for assessing their nutrient demand and supply status, which is beneficial to reveal their ecological strategies to adapt to the environment. This study measured the C, N, and P contents of stems, leaves, spikes, and roots of Roegneria yushuensis during the flowering, milk, dough, and mature stages, as well as its stoichiometric characteristics and allocation ratios. The aim was to explore the variations in the C, N, and P contents and stoichiometric ratios of the functional components of R. yushuensis throughout its growth stages, thereby providing a theoretical basis for the scientific harvest of R. yushuensis. The results showed that: 1) the mean C, N, and P contents of R. yushuensis were 408.52, 8.75, and 2.15 mg·g⁻¹, respectively. The mean ratios of C ꞉ N, C ꞉ P, and N ꞉ P were 65.52, 537.55, and 9.75, respectively. 2) the C, N, and P contents of R. yushuensis leaves, as well as the N content of spikes and the C content of roots, showed a decreasing trend along the growth stages. The P content of spikes decreased first and then increased. Except in the dough stage, the N and P contents were highest in the spikes throughout the other three stages, and the stoichiometric ratios of C, N, and P in the spikes continuously increased until the mature stage, reaching their maximum values. This indicated that nutrients gradually transferred to the spikes after entering the flowering stage, suggesting that R. yushuensis tends to allocate more resources to obtain more offspring as part of its growth strategy. 3) the coefficient of variation of each index was greater than 0.1 and less than 1.0, which indicated moderate variation. The variation source analysis showed that the contribution of the growth period to the variation in C content was greater than that of functional component differences, and the contribution of functional component differences to the N and P contents and the C ꞉ N, C ꞉ P, and N ꞉ P changes of R. yushuensis was greater than that during the growth period.