scholarly journals Leaf Age Compared to Tree Age Plays a Dominant Role in Leaf δ13C and δ15N of Qinghai Spruce (Picea crassifolia Kom.)

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 310 ◽  
Author(s):  
Li ◽  
Wang ◽  
Chen ◽  
Xu ◽  
Wu ◽  
...  
Keyword(s):  
Dominant Role ◽  
Leaf Age ◽  
Tree Age ◽  
Relative Importance ◽  
Ecological Stability ◽  
Δ13c And Δ15n ◽  
Picea Crassifolia ◽  
Significant Difference ◽  
Importance Analysis ◽  
Qinghai Spruce

Leaf stable isotope compositions (δ13C and δ15N) are influenced by various abiotic and biotic factors. Qinghai spruce (Picea crassifolia Kom.) as one of the dominant tree species in Qilian Mountains plays a key role in the ecological stability of arid region in the northwest of China. However, our knowledge of the relative importance of multiple factors on leaf δ13C and δ15N remains incomplete. In this work, we investigated the relationships of δ13C and δ15N to leaf age, tree age and leaf nutrients to examine the patterns and controls of leaf δ13C and δ15N variation of Picea crassifolia. Results showed that 13C and 15N of current-year leaves were more enriched than older ones at each tree age level. There was no significant difference in leaf δ13C values among trees of different ages, while juvenile trees (<50 years old) were 15N depleted compared to middle-aged trees (50–100 years old) at each leaf age level except for 1-year-old leaves. Meanwhile, relative importance analysis has demonstrated that leaf age was one of the most important indicators for leaf δ13C and δ15N. Moreover, leaf N concentrations played a dominant role in the variations of δ13C and δ15N. Above all, these results provide valuable information on the eco-physiological responses of P. crassifolia in arid and semi-arid regions.

Properties of Gliricidia Wood (Gliricidia sepium) lntercropped with Cocoa (Theobroma cocoa) in Malaysia

2014 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Mohd Helmy Ibrahim ◽  
Mohd Nazip Suratman ◽  
Razali Abd Kader
Keyword(s):  
Cell Wall ◽  
Specific Gravity ◽  
Moisture Content ◽  
Wall Thickness ◽  
Age Groups ◽  
Gliricidia Sepium ◽  
Cell Wall Thickness ◽  
Tree Age ◽  
Lumen Diameter ◽  
Significant Difference

Trees planted from agroforestry practices can become valuable resources in meeting the wood requirements of many nations. Gliricidia sepium is an exotic species introduced to the agricultural sector in Malaysia mainly for providing shade for cocoa and coffee plantations. This study investigates its wood physical properties (specific gravity and moisture content) and fibre morphology (length, lumen diameter and cell wall thickness) of G. sepium at three intervals according to age groups ( three, five and seven years of ages). Specific gravity (0.72) was significantly higher at seven years ofage as compared to five (0.41) and three (0.35) years age group with a mean of 0.43 (p<0.05). Mean moisture content was 58.3% with no significant difference existing between the tree age groups. Fibre diameter (22.4 mm) was significantly lower (p<0.05) for the trees which were three years of age when compared to five and seven years age groups (26.6 mm and 24. 7 mm), respectively. Means of fibre length, lumen diameter and cell wall thickness were 0.83 mm, 18.3 mm, and 6.2 mm, respectively, with no significant differences detected between trees in all age groups. Further calculation on the coefficient of suppleness and runkel ratio suggest that wood from G.sepium may have the potential for insulation board manufacturing and paper making. However, future studies should experiment the utilisation of this species for these products to determine its full potential.

The bonding variation of γ-TiAl during deformation

2021 ◽  
Vol 23 (6) ◽  
pp. 3905-3914
Author(s):  
Jinkai Wang ◽  
Xin Cui ◽  
Jianxin Huang ◽  
Hao Wang ◽  
Zhanpeng Lu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Local Energy ◽  
Relative Importance ◽  
Importance Analysis ◽  
Relative Importance Analysis

A relative importance analysis of various types of bonding through local energy and electronic structure was performed.

scholarly journals Foliar endophytes in trees varying greatly in age

2021 ◽  
Author(s):  
Zhongdong Yu ◽  
Hongru Ding ◽  
Kuocheng Shen ◽  
Fangfang Bu ◽  
George Newcombe ◽  
...  
Keyword(s):  
Exploratory Study ◽  
Leaf Age ◽  
Mechanistic Explanation ◽  
Tree Age ◽  
Botryosphaeria Dothidea ◽  
Platycladus Orientalis ◽  
Age Diversity ◽  
Components Analysis ◽  
Endophyte Community ◽  
Latent Pathogens

AbstractTemple trees, including the gymnosperm Platycladus orientalis and the angiosperm Styphnolobium japonicum, have been planted in China for thousands of years. Tree age thus varies widely from young to ancient trees. Foliar endophytes of P. orientalis and S. japonicum were surveyed in this exploratory study that was based on isolation into culture and sequencing of fungi from trees varying in age from 10 to 5000 years (P. orientalis) and from 10 to 1700 years (S. japonicum). Sequenced endophytes of P. orientalis and S. japonicum belonged to 24 and 16 fungal genera, respectively. Principal components analysis showed that 14 components were necessary to explain 90% of the variance in endophyte community structure in P. orientalis. In S. japonicum eight components were needed for 90%. It is against that backdrop of complex etiology in community structuring, that the relative frequencies (abundances) of 17 of the 24 endophytes from P. orientalis and 9 of the 16 from S. japonicum were significantly correlated with tree age. There were two major trends. Abundant fungal genera [Fusarium + Alternaria = 74.57% (P. orientalis) and 81.24% (S. japonicum)] tended to decline linearly with tree age. Most of the rare fungal genera, in contrast, increased in relative abundance linearly with tree age. Diversity (H′) and richness (Margalef) of endophyte communities in foliage thus increased as the trees aged. Relative abundances of pathogenic endophytes, or latent pathogens, (Pestalotiopsis funerea and Amyloporia subxantha in P. orientalis; Collectotrichum gloeosporioides and Botryosphaeria dothidea in S. japonicum) also increased linearly as the trees aged.Since leaf age does not vary with tree age in the deciduous S. japonicum, nor in the evergreen P. orientalis, ‘tree age’ currently lacks a mechanistic explanation for its apparent importance among common foliar endophytes.

Major Components of Green Urbanization and Their Relative Importance

2019 ◽  
pp. 315-339
Author(s):  
Subikash Mookherjee ◽  
Debasish Mondal
Keyword(s):  
Factor Analysis ◽  
Dominant Role ◽  
Negative Relationship ◽  
Positive Association ◽  
Relative Importance ◽  
Positive Relation ◽  
Economic Activities ◽  
Significant Phenomenon ◽  
Small Plot ◽  
Town Area

Aspirations for being urban in character are considered as a significant phenomenon of socio-economic development in developing countries. Urbanization, in economic sense only, means intensive economic activities by a large number of people in a relatively small plot of land, where secondary and tertiary sectors play a dominant role and where certain amenities are bound to be available for general citizens, though it doesn't seem complete without addressing the issue of nature. Though urbanization of an area is tried to be measured by some academicians through applying the method of indexing with available indicators and their data-driven weights, environmental issues are not incorporated there for any kind of factor analysis to identify their individual relative importance. This chapter intervenes at this juncture and focuses on construction of an urbanization index for some selected “town area units” belonging to some selected districts of West Bengal and run a factor analysis of it on some identified environmental factors. It observes negative relationship between QVSE and IGU, positive association between IGU and PR, and positive relation between IWDS and IGU.

The Effect of two different protein sources in the diet upon the incidence and prevalance of lameness in dairy cattle

1989 ◽  
Vol 1989 ◽  
pp. 66-66
Author(s):  
D N Logue ◽  
A Lawson ◽  
D J Roberts ◽  
E A Hunter
Keyword(s):  
Dairy Cattle ◽  
Crude Protein ◽  
Economic Consequences ◽  
Relative Importance ◽  
The West ◽  
Significant Difference ◽  
Series Of Experiments ◽  
Relationship Of ◽  
The Relationship ◽  
Locomotion Score

The importance of lameness in dairy cattle in UK in terms of its economic consequences and welfare considerations is well documented (Russel and others, 1982). While such epidemiological work has identified factors of importance in the aetiology of the various conditions associated with lameness it has been less successful in apportioning their relative importance, particularly for those conditions affecting the hoof. A series of experiments has been conducted at the West of Scotland College over the period 1983 to 1989 mainly investigating the relationship of nutrition and lameness. In one of these Manson and Leaver (1988) found a significant difference in the prevalence of lameness between two groups of cattle fed complete diets containing either 16.1 or 19.8% crude protein. They also found a significant increase in mean locomotion score (LS) and commented that further studies were needed to understand the dietary processes by which the hoof of the cow was predisposed to such problems.The objective of this experiment was to investigate the influence of the type of protein source in the concentrate upon the locomotion of the cows, the incidence and prevalence of lameness and finally on hoof hardness, shape, growth and wear.

Response of stem radial growth of Qinghai spruce ( Picea crassifolia ) to environmental factors in the Qilian Mountains of China

2017 ◽  
Vol 44 ◽  
pp. 76-83 ◽  
Author(s):  
Quanyan Tian ◽  
Zhibin He ◽  
Shengchun Xiao ◽  
Xiaomei Peng ◽  
Aijun Ding ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Radial Growth ◽  
Qilian Mountains ◽  
Picea Crassifolia ◽  
The Qilian Mountains ◽  
Qinghai Spruce
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