Prolonged drought regulates the silage quality of maize (Zea mays L.): Alterations in fermentation microecology.

Prolonged drought stress caused by global warming poses a tremendous challenge to silage production of maize. Drought during maize growth and development resulted in altered micro-environment for silage fermentation. How fermentation of silage maize responds to moisture scales remains uncharted territory. In this research, Maize water control trials were conducted and the silage quality and microbial community of drought-affected maize were determined. The results showed that drought stress significantly reduced the dry matter but increased root-to-shoot ratio, soluble sugar and malonaldehyde content in maize. Before fermentation, the crude protein, crude ash and acid detergent fiber contents were significantly increased but the ether extract content was decreased under drought. The crude protein and acid detergent fiber were significantly decreased in the drought affected group after fermentation. Furthermore, water stress at maize maturity stage greatly reduced the number of total bacteria in silage fermentation but increased the proportion of the lactobacillus and lactic acid content of silage. Drought stress alters the microbial ecosystem of the fermentation process and reconstitutes the diversity of the bacterial community and its metabolites. This study provides a theoretical basis for the study of changes in silage fermentation as affected by abiotic stresses.

Alpha-Linolenic Acid Mediates Diverse Drought Responses in Maize (Zea mays L.) at Seedling and Flowering Stages.

Water shortage caused by long-term drought is one of the most serious abiotic stress factors in maize. Different drought conditions lead to differences in growth, development, and metabolism of maize. In previous studies, proteomics and genomics methods have been widely used to explain the response mechanism of maize to long-term drought, but there are only a few articles related to metabolomics. In this study, we used transcriptome and metabolomics analysis to characterize the differential effects of drought stress imposed at seedling or flowering stages on maize. Through the association analysis of genes and metabolites, we found that maize leaves had 61 and 54 enriched pathways under seedling drought and flowering drought, respectively, of which 13 and 11 were significant key pathways, mostly related to the biosynthesis of flavonoids and phenylpropanes, glutathione metabolism and purine metabolism. Interestingly, we found that the α-linolenic acid metabolic pathway differed significantly between the two treatments, and a total of 10 differentially expressed genes and five differentially abundant metabolites have been identified in this pathway. Some differential accumulation of metabolites (DAMs) was related to synthesis of jasmonic acid, which may be one of the key pathways underpinning maize response to different types of long-term drought. In general, metabolomics provides a new method for the study of water stress in maize and lays a theoretical foundation for drought-resistant cultivation of silage maize.

[Control effects of different herbicides on weeds as well as their effects on growth and deve-lopment of broomcorn millet]. / 不同除草剂的田间杂草防效及对糜子生长发育的影响.

Selecting a herbicide suitable for broomcorn millet is a key issue in high efficiency and safe production of broomcorn millet and ecological environment improvement. We compared the control effects of 22 different herbicides on weeds as wells as their effects on growth and development of glutinous millet (Yumi 2) in the field. The results showed that, 1) soil applied Goyou, Butachlor, atrazine, and Benzipram, and stem- and leaf-applied WP mixture of tribenuron-methyl·carfentrazone-ethyl·MCPA-Na, Sigma Broad, Tengjing, Taoshi·Youxian and Kuofei had little phytotoxi-city, with broomcorn millet seedlings growing normally, and the other herbicides had phytotoxicities on broomcorn millet. 2) All the herbicides controlled weeds in the field to some extent, with better performance of soil applied herbicides than the stem- and leaf-applied ones, and affected plant height, functional leaf SPAD and spike weight per plant of broomcorn millet. 3) Compared with manual weeding, all herbicides reduced yields of glutinous millet. Compared with no herbicides application, some herbicides had yield-increasing effects. Among the soil applied herbicides, Go-you, Butachlor, atrazine, and Benzipram performed better in weeding control, increasing the yield of broomcorn millet by more than 60% compared with no herbicide control. Among the stem- and leaf-applied herbicides, Sigma Broad and WP mixture of tribenuron-methyl·carfentrazone-ethyl·MCPA-Na performed better in weeding control, increasing the yield of glutinous millet by more than 50% compared with no herbicide control. Therefore, applying 38% atrazine or 44% Monosulfuron to soil before the emergence of broomcorn millet, or stem- and leaf-applied 3.6% mesosulfuron-methyl or 55% WP mixture of tribenuron-methyl·carfentrazone-ethyl·MCPA-Na after the emergence of broomcorn millet, performed better in weeding control and with limited effects on the growth and development of broomcorn millet.