Leaf gas exchange and photosynthesis curves of Elymus nutans and Potentilla anserina under fencing and grazing conditions in the Qilian Mountains, Northwest China

Abstract

Potentilla anserina L. and Elymus nutans Griseb. are dominant species in the subalpine meadows of China. Grazing is one of the most important factors that influence community structure and productivity of subalpine meadows. Understanding how grazing changes photosynthetic capability is essential for preservation and restoration of grasslands. However, information about the effects of grazing on photosynthetic capability remains inadequate. Experiments were conducted in fencing and grazing areas in the Qilian Mountains, Northwest China. The leaf gas exchange and photosynthetic curves of P. anserina and E. nutans were measured at different growth stages. Results showed that grazing decreased the values of leaf gas exchange parameters, such as net photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO 2 concentration of P. anserina and E. nutans. In addition, grazing decreased the values of net photosynthetic rate-photosynthetically active radiation (P N-PAR) curve parameters, such as light-saturated net photosynthetic rate, apparent quantum efficiency, light compensation point, light saturation point, and dark respiration rate. Our results demonstrated that grazing was the primary limiting factor for photosynthesis of dominant grassland species in the study area.

Different grassland managements significantly change carbon fluxes in an alpine meadow

“…alpine meadow at the Qilian Mountains significantly increased after enclosure (Liu et al, 2019). In our study, ER of the artificial grassland was the lowest, and a study on Haibei alpine meadow also reported that ER of artificial grassland was lower, which was 1/2-1/3 of the WF grassland and natural grassland, respectively (Zhang Z. et al, 2018).…”

“…In China, 41.7% of the territory area is covered by grassland. Grassland not only provides abundant meat, milk, fur, and other products, but also has important ecological functions, such as regulating climate, conserving water, and sequestering carbon (Wang and Wang, 2019;Bai et al, 2020). As a sensitive and fragile area to global change, the Qinghai-Tibetan Plateau plays a key role in the regional and global carbon cycle (Yang W. et al, 2021).…”

“…Fence enclosure (hereinafter referred to as enclosure) and artificial grass planting are widely used to restore degraded grasslands. Enclosure is a natural renewal and restoration method for grasslands by fencing a fixed area of grass so that it is undisturbed by human activities, such as grazing (Wang et al, 2019;Sun et al, 2020). Artificial grass planting involves establishing annual or perennial artificial grass in a fence (Bai et al, 2018).…”

Application of Optimal Combined Microfertilizers of Boron, Molybdenum, and Copper Improves Root Tuber Yield Trait and Photosynthetic Response Characteristics in Pseudostellaria heterophylla

“…The characteristic parameters of diurnal variation of photosynthesis reflect the continuous ability of material accumulation and physiological metabolism of plants in a day. More importantly, they help when determining and analyzing the limiting factors in photosynthesis (Liu et al, 2019). Our study showed that the diurnal variation of P n in P. heterophylla leaves had an obvious photosynthetic midday depression in the current environmental conditions, when the local temperature had not yet reached a high in mid-May.…”

Analysis of Elymus nutans seed coat development elucidates the genetic basis of metabolome and transcriptome underlying seed coat permeability characteristics

“…Elymus nutans is a kind of perennial gramineous forage, which is widely distributed in the alpine region at an altitude of 3,000-5,000 m (Fu et al, 2014;Liu et al, 2019). It has strong cold resistance and can safely overwinter at low temperature (Ding et al, 2020).…”