Forage quality and physiological performance of mowed alfalfa (Medicago sativa L.) subjected to combined light quality and drought

Chunxia He; Yan Zhao; Yao Wang; Jinfeng Cai; Jun Gao; Jinsong Zhang

doi:10.3389/fpls.2022.1047294

Forage quality and physiological performance of mowed alfalfa (Medicago sativa L.) subjected to combined light quality and drought

Front Plant Sci. 2022 Nov 22:13:1047294. doi: 10.3389/fpls.2022.1047294. eCollection 2022.

Authors

Chunxia He^{1

2

3}, Yan Zhao⁴, Yao Wang^{1

2

3}, Jinfeng Cai², Jun Gao^{1

2

3}, Jinsong Zhang^{1

2

3}

Affiliations

¹ Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.
² Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
³ Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China.
⁴ College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, China.

Abstract

Alfalfa (Medicago sativa) can dwell in water-deficient habitats, where it is difficult to predict dry mass (DM) production and forage quality due to understory transmittance. Mowing is a recommended practice for alfalfa populations under drought, but its effect on forested land receives less attention. In a controlled indoor experiment, we found that drought better reduces shoot DM weight and crude fiber content (CFi) in blue light (33.7% red, 48.5% green, and 17.8% blue lights) than red light (71.7% red, 13.7% green, and 14.6% blue lights). Mowing decreases carbon (C) isotope signature (δ¹³C), CFi, and total C content in shoots but increases their accumulations in DM, nonstructural carbohydrates, and crude fat content (CFa). The results also demonstrated that mown alfalfa has higher starch content when exposed to green light (26.2% red, 56.4% green, and 17.4% blue lights) compared to the other two spectra. Multiple factorial regression indicated that higher soluble sugar content accounted for the increase of CFa and DM weight for CFi. Overall, mowing in blue-light-enriched understory stands is recommended and produces high-forage-quality alfalfa, which can be used as a lowered crude fiber component.

Keywords: alfalfa; climate change; forage quality; mowing; understory sunlight; water deficit.