scholarly journals A Bimodal Pattern and Age-Related Growth of Intra-Annual Wood Cell Development of Chinese Fir in Subtropical China

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanyan Jiang ◽  
Xiongqing Zhang ◽  
Sophan Chhin ◽  
Jianguo Zhang
Keyword(s):  
Growth Rate ◽  
Cell Formation ◽  
Cell Development ◽  
Chinese Fir ◽  
Subtropical China ◽  
Age Classes ◽  
Bimodal Pattern ◽  
Age Related ◽  
Xylem Formation ◽  
Number Of Cells

Age plays an important role in regulating the intra-annual changes in wood cell development. Investigating the effect of age on intra-annual wood cell development would help to understand cambial phenology and xylem formation dynamics of trees and predict the growth of trees accurately. Five intermediate trees in each stand (total of 5 stands) in five age groupings of Chinese fir (Cunninghamia lanceolata Hook.) plantations in subtropical China were monitored on micro-cores collected weekly or biweekly from January to December in 2019. We modeled the dynamics of wood cell development with a mixed effects model, analyzed the age effect on intra-annual wood cell development, and explored the contribution of rate and duration of wood cell development on intra-annual wood cell development. We found a bimodal pattern of wood cell development in all age classes, and no matter the date of peak or the maximal number of cells the bimodal patterns were similar in all age classes. In addition, compared with the older trees, the younger trees had the longest duration of wood cell development because of the later end of wood cell development and a larger number of wood cells. The younger trees had the faster growth rate than the older trees, but the date of the maximal growth rate in older trees was earlier than younger trees, which led to the production of more wood cells in the younger trees. Moreover, we found that the number of cells in wood cell formation was mostly affected by the rate (92%) rather than the duration (8%) of wood cell formation.

Altered stem cell regeneration in irradiated intestinal crypts of senescent mice

1998 ◽  
Vol 111 (16) ◽  
pp. 2297-2303 ◽  
Author(s):  
K. Martin ◽  
C.S. Potten ◽  
S.A. Roberts ◽  
T.B. Kirkwood
Keyword(s):  
Stem Cells ◽  
Growth Rate ◽  
Stem Cell ◽  
The Body ◽  
Growth Delay ◽  
Regenerative Capacity ◽  
Age Related ◽  
High Doses ◽  
Old Mice ◽  
Number Of Cells

Ageing is associated with a progressive deterioration in the functions of many organs within the body. In tissue with high cell turnover, the maintenance of the stem cells is of particular importance. Any accumulation of damage in stem cells may affect their function and hence threaten the homeostasis and regenerative capacity of the tissue. The small intestine represents a good model for the study of stem cells because of its spatial and hierarchical organisation. We have examined the effect of age on stem cell regenerative capacity after irradiation, using the microcolony assay. Crypt survival levels, the growth rate of surviving crypts, and the number of cells able to repopulate a crypt have been investigated by irradiating groups of 6–7 month old and 28–30 month old ICRFa male mice. After high doses of irradiation, the surviving crypts in old mice were both smaller and fewer in number than in young mice. The growth rate of surviving crypts was determined by measuring the crypt area and the number of cells/crypt at various times after 14 Gy irradiation. There was a growth delay of between about one half and one day in the older mice. Surprisingly, the number of clonogenic cells per crypt was estimated to be greater in the older mice. These studies indicate important age-related alterations in the capacity to regenerate the crypts after radiation damage.

scholarly journals Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China

2015 ◽  
Vol 12 (13) ◽  
pp. 10359-10387 ◽  
Author(s):  
W. Y. Dong ◽  
X. Y. Zhang ◽  
X. Y. Liu ◽  
X. L. Fu ◽  
F. S. Chen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Enzyme Activities ◽  
Microbial Community Composition ◽  
Soil Microbial Communities ◽  
Chinese Fir ◽  
Subtropical China ◽  
Nitrogen And Phosphorus ◽  
Soil Microbial ◽  
Nutrient Additions

Abstract. Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+) bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.

Carbon and nitrogen pools in Chinese fir and evergreen broadleaved forests and changes associated with felling and burning in mid-subtropical China

2005 ◽  
Vol 216 (1-3) ◽  
pp. 216-226 ◽  
Author(s):  
Yu Sheng Yang ◽  
Jianfen Guo ◽  
Guangshui Chen ◽  
Jinsheng Xie ◽  
Ren Gao ◽  
...  
Keyword(s):  
Chinese Fir ◽  
Subtropical China ◽  
Carbon And Nitrogen ◽  
Nitrogen Pools

scholarly journals Seasonal and needle age-related variations in the biochemical characteristics of Pinus nigra subsp. pallasiana (Lamb.) Holmboe

2018 ◽  
Vol 64 (No. 9) ◽  
pp. 379-386 ◽  
Author(s):  
Deligöz Ayşe ◽  
Bayar Esra ◽  
Genç Musa ◽  
Karatepe Yasin ◽  
Kirdar Erol ◽  
...  
Keyword(s):  
Pinus Nigra ◽  
Carbohydrate Content ◽  
Seasonal Patterns ◽  
Age Classes ◽  
Total Carbohydrate ◽  
Needle Age ◽  
Total Carbohydrate Content ◽  
Age Related ◽  
Pigment Contents ◽  
Carbohydrate Contents

Variations in the photosynthetic pigments and total carbohydrate contents of needles of different age classes (current-year, 1-year-old, 2-year-old and 3-year-old) of Pinus nigra subsp. pallasiana (Lambert) Holmboe trees in a young natural stand were investigated during the growing season. In current-year needles, total carbohydrate content was lower during June and July when the needle growth continued than in older age classes, but it was similar to other age classes in the months of August to October. Seasonal patterns of variations in total carbohydrate content were almost similar in 1-, 2-, and 3-year-old needles. Chlorophyll and carotenoid contents increased from May to June, remained relatively constant or declined slightly during summer and autumn in 1-, 2-, and 3-year-old needles. In October, the pigment content was highest in 1-year-old needles, and lowest in 3-year-old needles. Our study indicated that total carbohydrate and pigment contents were affected by needle age classes and seasons.

scholarly journals Evaluations of the Effects of Extremely Low-Frequency Electromagnetic Fields on Growth and Antibiotic Susceptibility ofEscherichia coliandPseudomonas aeruginosa

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
B. Segatore ◽  
D. Setacci ◽  
F. Bennato ◽  
R. Cardigno ◽  
G. Amicosante ◽  
...  
Keyword(s):  
Growth Rate ◽  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Antibiotic Susceptibility ◽  
Low Frequency ◽  
Antibiotic Sensitivity ◽  
Control Groups ◽  
E Coli ◽  
Extremely Low Frequency ◽  
Number Of Cells

We aimed to investigate the effects of exposure to extremely low-frequency electromagnetic fields (2 mT; 50 Hz) on the growth rate and antibiotic sensitivity ofE. coliATCC 25922 andP. aeruginosaATCC 27853. The electromagnetic field treatment significantly influenced the growth rate of both strains when incubated in the presence of subinhibitory concentrations of kanamycin (1 μg/mL) and amikacin (0.5 μg/mL), respectively. In particular, at 4, 6, and 8 h of incubation the number of cells was significantly decreased in bacteria exposed to electromagnetic field when compared with the control. Additionally, at 24 h of incubation, the percentage of cells increased (P. aeruginosa∼42%;E. coli∼5%) in treated groups with respect to control groups suggesting a progressive adaptive response. By contrast, no remarkable differences were found in the antibiotic susceptibility and on the growth rate of both bacteria comparing exposed groups with control groups.

scholarly journals PHAEODACTYLUM TRICORNUTUM MICROALGAE GROWTH RATE IN HETEROTROPHIC AND MIXOTROPHIC CONDITIONS

2009 ◽  
Vol 8 (1) ◽  
pp. 84 ◽  
Author(s):  
K. C. C. Morais ◽  
R. L. L. Ribeiro ◽  
K. R. Santos ◽  
D. M. Taher ◽  
A. B. Mariano ◽  
...  
Keyword(s):  
Growth Rate ◽  
Phaeodactylum Tricornutum ◽  
Agricultural Land ◽  
Production Costs ◽  
Biofuel Production ◽  
Glycerol Concentration ◽  
Microalgae Biomass ◽  
Dry Biomass ◽  
Number Of Cells ◽  
Microalgae Growth

The Brazilian National Program for Biofuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO2. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10th and 14th days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. Was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l-1. In order to compare simulation data with experimental data, we calculated the dry weight in 8 points in the course of sixteen days. In this way, it was possible to assess graphically biomass concentration versus time through the experiments and by numerical simulation. It was identified that the simulation results were consistent with the experiments and that the addition of glycerol greatly influenced the growth of microalgae. In the present analysis, the glycerol added increased 30% in biomass.

scholarly journals How Precise are Size-Based Age Estimations in the Sand Lizard (Lacerta Agilis)?

2011 ◽  
Vol 56 (1-4) ◽  
pp. 11-17 ◽  
Author(s):  
Bartosz Borczyk ◽  
Łukasz Paśko
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Life Span ◽  
Age Estimation ◽  
The Body ◽  
Average Error ◽  
Ecological Studies ◽  
Age Classes ◽  
Sand Lizard ◽  
Lacerta Agilis

How Precise are Size-Based Age Estimations in the Sand Lizard (Lacerta Agilis)?Reptiles show a positive correlation between age and body size and it is common practice to infer the age of an animal from its size. However, the growth rate often differs between individuals, thus such practice may lead to false conclusions. Because age of an animal is a very important factor in many ecological studies, it should be determined with a minimum of error. Here, we compare the body size distribution among different age classes of the sand lizard (Lacerta agilis) to infer if it is possible to correctly determine their age on the basis of the body length. Our results show that the average error in age estimation on the basis of the lizard size is 1.36 year which is approximately 1/3 the average sand lizard life span.

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