Effects of litter addition and simulated nitrogen and phosphorus deposition on lignin degradation and carbon release from Korean pine litter

2021 ◽  
Vol 41 (16) ◽  
Author(s):  
郭绮雯,段文标,刘玉萍,陈立新,李常准,于颖颖,李少然,李亦菲 GUO Qiwen
2016 ◽  
Author(s):  
Jinniu Wang ◽  
Bo Xu ◽  
Yan Wu ◽  
Jing Gao ◽  
Fusun Shi

Abstract. Litters of reproductive organs have been rarely studied, despite their role in allocating nutrients for offspring reproduction. This study determines the mechanism through which flower litters efficiently increase the available soil nutrient pool. Field experiments were conducted to collect plant litters and calculate biomass production in an alpine meadow of the eastern Tibetan Plateau. Carbon, nitrogen, phosphorus, lignin, cellulose, and their relevant ratios of litters were analyzed to identify their decomposition features. A pot experiment was performed to determine the effects of litter addition on soil nutrition pool by comparison between the treated and control samples. Litter-bag method was used to verify decomposition rates. The flower litters of phanerophyte plants were comparable with non-flower litters. Biomass partitioning of other herbaceous species accounted for 10%–40% of the aboveground biomass. Flower litter possessed significantly higher N and P levels but less C/N, N/P, lignin/N, and lignin and cellulose concentrations than leaf litter. Flower litter fed soil nutrition pool more efficiently because of their faster decomposition rate and higher nutrient contents. Litter-bag experiment confirmed that the flower litters of Rhododendron przewalskii and Meconopsis integrifolia decomposes approximately three times faster than mixed litters within 50 days. Moreover, the findings of the pot experiment indicated that flower litter addition significantly increased the available nutrient pool. Flower litter influenced nutrition cycling in alpine ecosystems, as evident by its non-ignorable production and significantly faster decomposition. The underlying mechanism can enrich nutrients, which return to the soil, and non-structural carbohydrates, which feed and enhance the transitions of soil microorganisms.


2020 ◽  
Vol 85 ◽  
pp. 47-58
Author(s):  
Y Jiang ◽  
Y Liu

Various studies have observed that increased nutrient supply promotes the growth of bloom-forming cyanobacteria, but only a limited number of studies have investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. We investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nutrients significantly promoted the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under high nutrient levels. Overexpressed proteins related to photosynthesis, and amino acid synthesis, were responsible for the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth by inducing the overexpression of the cell division regulatory protein FtsZ. NtcA, that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis, was overexpressed under the high nitrogen condition, which consequently induced overexpression of 2 microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provides a comprehensive description of changes in the proteome of M. aeruginosa in response to an increased supply of 2 key nutrients.


Author(s):  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova

Identification of water masses in areas with complex water dynamics is a complex task, which is usually solved by the method of expert assessments. In this paper, it is proposed to use a formal procedure based on the application of the method of optimal multiparametric analysis (OMP analysis). The data of field measurements obtained in the 68th cruise of the R/V “Academician Mstislav Keldysh” in the summer of 2017 in the Barents Sea on the distribution of temperature, salinity, oxygen, silicates, nitrogen, and phosphorus concentration are used as a data for research. A comparison of the results with data on the distribution of water masses in literature based on expert assessments (Oziel et al., 2017), allows us to conclude about their close structural similarity. Some differences are related to spatial and temporal shifts of measurements. This indicates the feasibility of using the OMP analysis technique in oceanological studies to obtain quantitative data on the spatial distribution of different water masses.


2019 ◽  
Vol 55 (3) ◽  
pp. 29-43 ◽  
Author(s):  
P. D. Klochenko ◽  
T. F. Shevchenko ◽  
I. N. Nezbrytskaya ◽  
Ye. P. Belous ◽  
Z. N. Gorbunova ◽  
...  

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