scholarly journals Effects of different concentrations of nitrogen additions on fine root morphological characteristics in permafrost peatland in the Daxing'an Mountains

2021 ◽  
Vol 41 (20) ◽  
Author(s):  
高晋丽，宋艳宇，宋长春，张豪，谭稳稳，杜宇 GAO Jinli
Keyword(s):  
Fine Root ◽  
Morphological Characteristics ◽  
Daxing’An Mountains ◽  
Nitrogen Additions

Fine root morphological characteristics and its functions in mature Chinese fir plantations along an elevation gradient in Dabie Mountains

2020 ◽  
Vol 40 (2) ◽  
Author(s):  
李爱琴 LI Aiqin ◽  
张莎莎 ZHANG Shasha ◽  
王会荣 WANG Huirong ◽  
张丹丹 ZHANG Dandan ◽  
赵晓雅 ZHAO Xiaoya ◽  
...  
Keyword(s):  
Fine Root ◽  
Elevation Gradient ◽  
Morphological Characteristics ◽  
Chinese Fir ◽  
Dabie Mountains

Soil respiration and its components respond asymmetrically to throughfall reduction and nitrogen additions in a subtropical Moso bamboo forest in the Southwest China

2020 ◽  
Author(s):  
Yi Wang ◽  
Shirong Liu ◽  
Junwei Luan
Keyword(s):  
Global Change ◽  
Soil Respiration ◽  
Southwest China ◽  
Fine Root ◽  
Global Climate ◽  
Moso Bamboo ◽  
Change Factors ◽  
The Impact ◽  
Throughfall Reduction ◽  
Nitrogen Additions

<p>The roles of multiple global change are expected for many terrestrial ecosystems in future. As two main global change factors, the impact of drought and nitrogen deposition and their interaction on soil respiration and its components (R) remains unclear. To explore the responses of soil respiration (R<sub>s</sub>), autotrophic respiration (R<sub>a</sub>) and heterotrophic respiration (R<sub>h</sub>) to multiple global change factors, we established a field experiment of throughfall reduction and nitrogen additions in a subtropical Moso bamboo (<em>Phyllostachys heterocycla</em>) forest in the Southwest China, using a 4 × 4 completely randomized design. Results showed that bivariate exponential equation with soil temperature (T) and soil moisture (SWC) (R=a.e<sup>bT</sup>.SWC<sup>c</sup>) was fitted to predict R<sub>s</sub>, R<sub>a</sub> and R<sub>h</sub>. Throughfall reduction, nitrogen additions and their interaction had no effect on annual mean R<sub>s</sub> and R<sub>a</sub>, but nitrogen additions significantly depressed annual mean R<sub>h</sub>. Nitrogen additions significantly decreased contribution of R<sub>h</sub> to R<sub>s</sub> and increased contribution of R<sub>a</sub> to R<sub>s</sub>, however, the contributions were non-responsive under throughfall reduction. The more positive effect of nitrogen additions on the contribution of R<sub>a</sub> to R<sub>s</sub> was appeared compared with that of throughfall reduction, thereby more negative effect on the contribution of R<sub>h</sub> to R<sub>s</sub>. The fine root biomass, fine root carbon and nitrogen storage regulated R<sub>s</sub>, while fine root phosphorus storage determined R<sub>a</sub>. The R<sub>h</sub> was negatively correlated with vector lengths, thus suggesting that microbial carbon limitation caused the decline of R<sub>h</sub>. Our findings demonstrate that the nitrogen additions played overriding role than throughfall reduction in affecting the contribution of R<sub>a</sub> and R<sub>h</sub> to R<sub>s</sub>. Moreover, the negative response of temperature sensitivity of R<sub>s</sub> and R<sub>h</sub> to nitrogen additions, suggesting that that the nitrogen additions may weaken the positive response of soil CO<sub>2</sub> emission to global climate warming. Our study highlights asymmetrical responses of R<sub>s</sub>, R<sub>a</sub> and R<sub>h </sub>to throughfall reduction and nitrogen additions and could enhance accurate predictions of soil carbon dynamics in response to multiple global climate change in future.</p>

Direct and indirect effects of nitrogen additions on fine root decomposition in a subtropical bamboo forest

2014 ◽  
Vol 389 (1-2) ◽  
pp. 273-288 ◽  
Author(s):  
Li-hua Tu ◽  
Yong Peng ◽  
Gang Chen ◽  
Hong-ling Hu ◽  
Yin-long Xiao ◽  
...  
Keyword(s):  
Indirect Effects ◽  
Fine Root ◽  
Root Decomposition ◽  
Bamboo Forest ◽  
Direct And Indirect Effects ◽  
Fine Root Decomposition ◽  
Nitrogen Additions

Effects of thinning intensity on fine root biomass and morphological characteristics of middle-aged Pinus tabulaeformis plantations in the Huanglong Mountains

2017 ◽  
Vol 37 (9) ◽  
Author(s):  
尤健健 YOU Jianjian ◽  
张文辉 ZHANG Wenhui ◽  
邓磊 DENG Lei ◽  
余碧云 YU Biyun ◽  
李罡 LI Gang ◽  
...  
Keyword(s):  
Root Biomass ◽  
Fine Root ◽  
Morphological Characteristics ◽  
Fine Root Biomass ◽  
Pinus Tabulaeformis ◽  
Middle Aged ◽  
Thinning Intensity

Interactions between Soil Water and Fertilizer Application on Fine Root Biomass Yield and Morphology of Catalpa bungei Seedlings

2014 ◽  
Vol 700 ◽  
pp. 323-333
Author(s):  
Quan Qiu ◽  
Ji Yue Li ◽  
Jun Hui Wang ◽  
Qian He ◽  
Yan Su ◽  
...  
Keyword(s):  
Soil Water ◽  
Root Biomass ◽  
Biomass Yield ◽  
Fine Root ◽  
Morphological Characteristics ◽  
Fertilizer Application ◽  
Fine Root Biomass ◽  
Catalpa Bungei ◽  
Positive Effect ◽  
Main Factor

Through a pot experiment using rotatable central composite design (RCCD) with three factors, five levels, twenty runs, fine root biomass yield (BY), total length (TL), surface area (SA) and total volume (TV) of clone 004-1 ofCatalpa bungeiseedlings under different treatments was determined, and then the mathematical models were established to study the main factor effects, monofactor effect and coupling effects of soil water(W), nitrogen application (N) and phosphorus application (P) on fine root biomass yield and morphological characteristics ofC.bungeiseedlings. Results showed thatNhad a significantly positive effect on BY, TL, SA and TV,Phad a significantly positive effect on BY, TL and SA,Whad a significantly negative effect on TL and SA, and the size sequence of main factor effects was:N>P>W. Monofactor effect analysis results showed that the values of BY, TL, SA and TV first increased and then decreased withNincreasing, and BY, TL, SA increased linearly withPincreasing. ForW, TL, SA decreased linearly and TV first increased and then decreased withWincreasing. Interaction ofW×Nhad a significantly positive effect on BY, TL, SA and TV ofC. bungeiseedlings, and the values of four parameters increased gradually withWandNincreasing. However, interactions ofW×P,N×Pboth affected four parameters non-significantly. In conclusion, root biomass and morphological characteristics ofC. bungeiseedlings showed distinct responses to soil water and fertilizer factors, andW, NandPalso influenced fine root growth ofC. bungeiseedlings differently. We recommended that fine root growth ofC. bungeiseedlings could be promoted by the rational method combined irrigation and fertilizer application.

Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus

1971 ◽  
Vol 29 ◽  
pp. 338-339
Author(s):  
M. J. Kramer ◽  
Alan L. Coykendall
Keyword(s):  
Cell Wall ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Genetic Heterogeneity ◽  
Morphological Characteristics ◽  
Electron Microscopic ◽  
Dna Reassociation ◽  
Wall Ultrastructure

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.

Aberrant Type C Virus Production in a Cell Line Derived from Balb/3T3

1972 ◽  
Vol 30 ◽  
pp. 286-287
Author(s):  
N. Savage ◽  
A. Hackett
Keyword(s):  
Electron Microscopy ◽  
Cell Line ◽  
Leukemia Virus ◽  
Morphological Characteristics ◽  
Virus Production ◽  
Oncogenic Viruses ◽  
Endogenous Virus ◽  
Virus Particles ◽  
Moloney Leukemia Virus ◽  
A Cell

A cell line, UC1-B, which was derived from Balb/3T3 cells, maintains the same morphological characteristics of the non-transformed parental culture, and shows no evidence of spontaneous virus production. Survey by electron microscopy shows that the cell line consists of spindle-shaped cells with no unusual features and no endogenous virus particles.UC1-B cells respond to Moloney leukemia virus (MLV) infection by a change in morphology and growth pattern which is typical of cells transformed by sarcoma virus. Electron microscopy shows that the cells are now variable in shape (rounded, rhomboid, and spindle), and each cell type has some microvilli. Virtually all (90%) of the cells show virus particles developing at the cell surface and within the cytoplasm. Maturing viruses, typical of the oncogenic viruses, are found along with atypical tubular forms in the same cell.

DNA nick end labeling: a reliable marker for apoptosis?

1995 ◽  
Vol 53 ◽  
pp. 962-963
Author(s):  
Anne F. Bushnell ◽  
Sarah Webster ◽  
Lynn S. Perlmutter
Keyword(s):  
Cell Death ◽  
Cultured Cells ◽  
Apoptotic Cell ◽  
Morphological Characteristics ◽  
Detection Methods ◽  
Tissue Preparation ◽  
Preparation Methods ◽  
Dna Laddering ◽  
Disease States ◽  
Reliable Marker

Apoptosis, or programmed cell death, is an important mechanism in development and in diverse disease states. The morphological characteristics of apoptosis were first identified using the electron microscope. Since then, DNA laddering on agarose gels was found to correlate well with apoptotic cell death in cultured cells of dissimilar origins. Recently numerous DNA nick end labeling methods have been developed in an attempt to visualize, at the light microscopic level, the apoptotic cells responsible for DNA laddering.The present studies were designed to compare various tissue processing techniques and staining methods to assess the occurrence of apoptosis in post mortem tissue from Alzheimer's diseased (AD) and control human brains by DNA nick end labeling methods. Three tissue preparation methods and two commercial DNA nick end labeling kits were evaluated: the Apoptag kit from Oncor and the Biotin-21 dUTP 3' end labeling kit from Clontech. The detection methods of the two kits differed in that the Oncor kit used digoxigenin dUTP and anti-digoxigenin-peroxidase and the Clontech used biotinylated dUTP and avidinperoxidase. Both used 3-3' diaminobenzidine (DAB) for final color development.

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