Effects of formic acid, formaldehyde and two levels of tannic acid on changes in the distribution of nitrogen (N) and plant enzymatic activity during ensilage of lucerne (Medicago sativa) were studied. Lucerne [300 g dry matter (DM) kg )1 forage] silages were prepared untreated (control) and with formic acid (4 g kg )1 DM), formaldehyde (1 g kg )1 DM) and two levels of tannic acid (20 and 50 g kg )1 DM) as additives. Inhibition of proteolysis by formic acid was more effective than the other additives during the first 7 d of ensiling. Tannic acid was as effective at inhibiting production of nonprotein-N, ammonia-N and free amino acid-N as formic acid and formaldehyde. However, increased concentrations of non-protein-N and free amino acid-N in silage from day 1 to 35 of ensiling were less with the higher level of tannic acid than that in the control and other additive-treated silages. Carboxypeptidase lost its activity slowly with increasing time of ensiling. At day 2, it still had 0AE79 of the original activity in the control silage. After 21 d of ensiling, high levels of carboxypeptidase activity, proportionately 0AE41, 0AE49, 0AE10, 0AE35 and 0AE30 of the original activity, remained in the control silage, and silages made with formic acid, formaldehyde, and low and high levels of tannic acid respectively. There were higher levels of activity of acid proteinase in formic acid-treated silage than in the control silage until day 2 of ensilage indicating that the reduction of proteolysis by formic acid was probably due to acidifying the forage below the pH optima of plant protease. Aminopeptidase activity in all silages declined rapidly after ensiling.

No abstract

Ralstonia solanacearum is a major phytopathogenic bacterium that attacks many crops and other plants around the world. In this study, a novel actinomycete, designated strain NEAU-SSA 1T, which exhibited antibacterial activity against Ralstonia solanacearum, was isolated from soil collected from Mount Song and characterized using a polyphasic approach. Morphological and chemotaxonomic characteristics of the strain coincided with those of the genus Streptomyces. The 16S rRNA gene sequence analysis showed that the isolate was most closely related to Streptomyces aureoverticillatus JCM 4347T (97.9%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain formed a cluster with Streptomyces vastus JCM4524T (97.4%), S. cinereus DSM43033T (97.2%), S. xiangluensis NEAU-LA29T (97.1%) and S. flaveus JCM3035T (97.1%). The cell wall contained LL-diaminopimelic acid and the whole-cell hydrolysates were ribose, mannose and galactose. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), hydroxy-phosphatidylethanolamine (OH-PE), phosphatidylinositol (PI), two phosphatidylinositol mannosides (PIMs) and an unidentified phospholipid (PL). The menaquinones were MK-9(H4), MK-9(H6), and MK-9(H8). The major fatty acids were iso-C17:0, C16:0 and C17:1 ω9c. The DNA G+C content was 69.9 mol %. However, multilocus sequence analysis (MLSA) based on five other house-keeping genes (atpD, gyrB, recA, rpoB, and trpB), DNA–DNA relatedness, and physiological and biochemical data showed that the strain could be distinguished from its closest relatives. Therefore, it is proposed that strain NEAU-SSA 1T should be classified as representatives of a novel species of the genus Streptomyces, for which the name Streptomyces sporangiiformans sp. nov. is proposed. The type strain is NEAU-SSA 1T (=CCTCC AA 2017028T = DSM 105692T).

Accurately quantifying evapotranspiration (ET) is crucial to fully understanding regional water resource management and potential feedbacks to climate change in alpine grasslands. The quantitative relationships between ET and environmental controls were investigated by a continuous eddy covariance dataset from June 2014 to December 2016 over an alpine Kobresia meadow on the northeastern Qinghai‐Tibetan Plateau. The results showed that daily ET averaged 1.7± 1.5 mm/day (Mean ± 1 S.D.), with values of 2.9 ± 1.3, 1.6 ± 1.0, and 0.7± 0.6 mm/day during the growing season, seasonal transition period, and nongrowing season, respectively. Cumulative growing season ET was 63% of annual ET with little annual variability (349.9 ± 12.1 mm). Paired‐samples t‐test analysis indicated that monthly ET was larger than maximum potential ET derived from the FAO‐56 reference crop ET by 17% (p < .001, N = 12) in the growing season, likely because of high aerodynamic conductance, but was less than the minimum equilibrium ET by 19% (p < .001, N = 14) during the nongrowing season owing to limited surface moisture availability from the frozen soil. The structural equation models revealed that daily ET was mostly dominated by net radiation (the standardized coefficient of the total effect was 0.78). Soil surface moisture and leaf area index played secondary roles in daily ET variability during the nongrowing season and growing season, respectively. At an annual scale, the bulk surface conductance (8.25–10.65 mm/s), decoupling coefficient (0.43–0.48, 0.61 in the growing season), and the ratio of ET to equilibrium ET (1.08–1.33) were consistent with the strongly energy‐limited conditions in the alpine meadow. This study indicated that initial vegetation rehabilitation on the severely degraded meadow would be at the risk of rapid water consumption in humid alpine regions.