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1.
Gaku Hitusma Takayuki Ota Tatsuo Kanazashi Takashi Masaki 《Journal of Forest Research》2006,11(4):281-287
We investigated changes in sapling growth and morphology of Thujopsis dolabrata var. hondai (hiba) for 7 years after release from suppressed lighting by selection cutting. We examined changes in aboveground biomass,
elongation of stems and lateral branches, and annual diameter increment at the stem base. Vertical distributions of leaves
per branch and per individual were also measured for morphological analysis. Under the suppressed condition before cutting,
the crown consisted of orthotropic lateral branches, elongating up to the top of the stem or farther, and no branch was aborted.
This crown type with large crown depth and concavity of the upper part had a bowl-like appearance. After the selection cutting,
relative light intensity on the saplings increased from 4% to 26%. The increment enhanced aboveground biomass and stem elongation
7 years after the cutting. Diameter growth at the stem base was particularly accelerated 2 years after the cutting. While
crown shape transformation of the saplings was not conspicuous at 7 years after the cutting, some released saplings showed
a superior stem elongation ratio to that of the lateral branches. Thus, the upper part of the crown of these saplings changed
from a bowl-like shape to a convex shape like that of a dome. Our study suggested that suppressed hiba saplings with the unique
bowl-shaped crown enhanced their growth rates rapidly in response to improved light conditions, but required much more than
7 years for the full process of crown transformation for us to identify future trees in this stand.
An erratum to this article is available at. 相似文献
2.
Takuya Kajimoto Gaku Hitsuma Takashi Masaki Tatsuo Kanazashi 《Journal of Forest Research》2006,11(2):107-116
We analyzed the growth patterns of Thujopsis dolabrata var. hondai trees in an old plantation (161 years old), where no silvicultural treatments (e.g., thinning) have been conducted since
the initial planting. The analysis focused on understanding individual growth under a long-term self-thinning process, and
the stand-level stemwood production at the mature stage was evaluated. Nine canopy-layer trees and one suppressed tree were
used for the analysis of annual increments in stem diameters, heights, and stemwood volumes for a given past year using the
ring-width data. Both the diameter (at basal portion) and height of all the canopy-layer trees increased at similar rates
during the early stage (i.e., 60–70 years after planting); however, after this period, only the height growth rates declined
sharply. The annual growth rates of stemwood volume also simultaneously leveled off at the stand age of 40–60 years. Subsequently,
the patterns diverged conspicuously, e.g., the growth rates were maintained or increased in some individuals, while it gradually
decreased in the case of others until the present year. The divergence of growth pattern was likely to be triggered by intertree
competition at several decades after the onset of canopy closure. The current stemwood production of the sample trees, including
the suppressed one, was positively correlated with certain size parameters such as stem diameter at breast height and sapwood
area at a height of 4 m. Based on the diameter-base allometry, the total stand stemwood production was estimated to be about
12.8 m3 ha−1 year−1. This estimate was higher than those of some old natural T. dolabrata forests (2.0–8.6 m3 ha−1 year−1) that have been well managed by repetitive selection thinning. Furthermore, individual mean stemwood production of the study
plantation (0.03 m3 tree−1 year−1) was within the range of these natural stands (0.01–0.05 m3 tree−1 year−1). These comparisons suggested that the old T. dolabrata plantation still maintained a relatively high stemwood production potential despite the absence of artificial controls of
tree density in the past. In terms of timber production, this fact implied that a rather long rotation (>100 years) can be
applicable in the management of T. dolabrata plantations. 相似文献
3.
Methyl esters of higher fatty acids were detected from the healthy bark of Thujopsis dolabrata var. hondae but not from the bark of the resinous stem canker of T. dolabrata var. hondae. This difference enabled us to distinguish healthy trees from diseased ones. Fourteen diterpenes were also isolated from the n-hexane extracts of the bark-glued resin taken from the resinous stem canker of T. dolabrata var. hondae. Of these diterpenes, abietane diterpenes [abieta-7,13-diene (1), abietinol (2), dehydroabietinol (4)], pimarane diterpene [sandaracopimaric acid (8)], and labdane diterpenes [manool (10), torulosol (11), torulosal (12), cupressic acid (13)] were first isolated from T. dolabrata var. hondae.Part of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999 相似文献
4.
Effects of drought stresses induced by polyethylene glycol (PEG) (0.0%, 10%, 15%, 20%, 25%, and 30%, with four replicates)
on germination of Mongolian pine (Pinus sylvestris var. mongolica) seeds produced in plantations (southern Keerqin sandy land) and natural forests (Hulunbeier sandy plain) were observed.
The results indicated that the seeds from both provenances did not germinate when PEG concentration was more than 25%. The
time of initial germination and that of its completion of stressed seeds from both provenances were delayed when compared
with the unstressed seeds. The germination capacity and germination rate of natural seeds were significantly higher than those
of plantation seeds for all treatment levels (P < 0.05). The mean growth rates of radicle and hypocotyl from natural seeds were significantly higher than those from plantation
seeds at all treatment levels below 20% PEG treatment (P < 0.05). The ratios of radicle to hypocotyl of 20% PEG treatment were significant higher than those of the corresponding
controls for both provenances (P < 0.05). These results suggested that Mongolian pine seeds/seedlings had stronger resistance to PEG drought stresses; 10%
PGE stress did not significantly influence germination. Natural seeds exhibited more resistance to PEG stress than plantation
seeds. It was concluded that drought stress on seed germination might be one cause of obstructed natural regeneration of Mongolian
pine plantations on sandy land. It is recommended that natural seeds be used for afforestation, and light drought stress (e.g.,
10% PEG stress) may be useful in improving seed germination and the growth of radicles and hypocotyls. 相似文献
5.
This paper dealt with the studying the germination percentage, germination potential and analyzing the germination of the
seeds with different treatments by systematic statistics method. Seeds were collected from 14 provenances in September 1994.
The results indicated that the germination percentage and germination potential of the seeds in various provenances were different.
Both indexes in Nanchang, area was much lower than those in the rest provenances. The germination percentage and germination
potential of the seeds in different provenance declined after the seeds were treated with aging for one year. The light treatment
might promotes the germination percentage more effectively than the germination potential. In addition, fuzzy cluster may
reflect the relationship among germination in different provenances.
(Responsible Editor: Dai Fangtian) 相似文献
6.
A monoterpene and 15 diterpenes were isolated from the ethyl acetate extracts of the bark-glued resin from the resinous stem canker ofThujopsis dolabrata var.hondae Makino. A monoterpene (nezukone20) and 4 diterpenes (acetyl torulosol5, acetyl isocupressic acid8, acetyl abietinol11, and 7-methoxytotarol18) were characteristic constituents of the ethyl acetate extracts but were absent in then-hexane extracts from the resinous stem canker ofT. dolabrata var.hondae. These terpenes were first isolated fromT. dolabrata var.hondae andT. dolabrata. The available literature suggests that diterpene18 is a new compound. The resinous stem canker ofChamaecyparis obtusa Endlicher contained larger amounts of manool1,trans-communic acid6, and ferruginol12 and smaller amounts of isocupressic acid7 and abietinol10 than the resinous stem canker ofT. dolabrata var.hondae. The concentration of18 was less than 2% in the extracts, and the resinous stem canker ofC. obtusa lacked this compound. The resinous stem cankers ofC. obtusa andT. dolabrata var.hondae provided extracts 15.6 and 4.96 times, respectively, heavier than the healthy ones. Large differences in the ratios and compositions of terpenes were also observed between the resinous stem canker and the healthy trees. Terpenes isolated from the extracts contained many kinds of diterpene, especially the labdane-type diterpenes, in these diseased trees. These results suggest that the presence of labdane-type diterpenes is closely associated with the resinous stem canker or the causal fungi of this disease.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto, April 2000 相似文献
7.
以6处不同种源的南方红豆杉种子为研究对象,对种子千粒重、优良度、生活力、发芽率和发芽势进行比较分析的结果表明:不同种源的南方红豆杉种子千粒重范围为86.0—90.25g、优良度为85.0%-90.0%、有生活力的平均值为80.2%;发芽率的范围为64.6%-79.4%、发芽势的平均天数为15.17天;综合分析可知,九江市和桑植县的发芽特性最好,采用40%温水浸种20min,0.5g/kg赤霉素溶液浸种24h后,翌春播种后发芽率最高,为89.33%。 相似文献
8.
Understanding the germination traits of plants is important not only for understanding natural regeneration processes but
also for developing seedling production techniques for planting. Sabina vulgaris Ant. is a common species used for reforestation in semi-arid areas of the Mu-Us Desert, in Inner Mongolia, China, but its
extremely low germination rate, both in situ and in vivo, is a bottleneck for seedling production. Sulfuric acid pretreatment
was applied to improve germination, and the germination rate was compared for different soaking time (10, 30, 60, 90, and
120 min), different temperatures (10, 15, 20, 30, and 35°C) and under different lighting conditions (dark and light). Sulfuric
acid treatment gave a high germination rate, reaching 60% at 30 days after sowing. However, the non-treated seeds produced
no germination. The optimal treatment time in sulfuric acid was 120 min. Germination after sulfuric acid treatment increased
at incubation temperatures from 10 to 30°C, but decreased at 35°C. Incubation at 25–30°C gave maximum germination of more
than 50%. Light treatment had little effect on germination. Pretreatment with sulfuric acid improved water absorption by the
embryo by creating cracks and cavities in the seed coat tissue. These results indicated that S. vulgaris seeds have physical dormancy caused by their hard seed coats, which prevents absorption of water into the embryo. A combination
of pretreatment with sulfuric acid and incubation at 25–30°C was most effective in improving the germination of S. vulgaris seeds. 相似文献
9.
Qiong Zhao Xingyu Liu Dehui Zeng Jinhuan Liu Yalin Hu 《Frontiers of Forestry in China》2009,4(1):85-89
In order to find out the best foliar diagnostic index of phosphorus (P) nutrition in Mongolian pine (Pinus sylvestris var. mongolica) in the southeastern Keerqin Sandy Lands, the concentrations of total nitrogen (N), inorganic P, organic P and total P in
needles of different ages and soil available P were examined. The results show that in the study area, soil available P was
rather low (0.12–0.63 mg/kg) and was significantly correlated with inorganic P (cPi) and total P (cPt) concentrations in current
year needles of Mongolian pine. The significant correlation between soil available P and needle cPt derived from the significant
correlation between cPi and cPt. Compared with cPt, cPi did reflect the level of soil P supply more accurately and more directly.
__________
Translated from Chinese Journal of Applied Ecology, 2008, 19(3): 494–498 [译自: 应用生态学报] 相似文献
10.
The germination of common alder (Alnus glutinosa (L.) Gaertn.) and downey birch (Betula pubescens Ehrh.) seeds is often poor in bare-root nurseries. The effect of a variety of seed coverings and a few seed pretreatments
on seedling emergence was examined in this study in an attempt to address this problem. Seeds of each species were sown in
trays containing nursery soil, covered with grit, gravel, sand, combinations of these coverings, a hydromulch or a sealed
plastic cloche and then incubated for 6 weeks at 17–20°C. The grit combined with sand or gravel, the hydromulch and the cloche
increased seedling emergence when compared with the standard grit. In another experiment, seeds of each species were fully
imbibed (FI) (>50% moisture content, MC), as per standard practice, or adjusted to target MC (TMC) (30–35% MC) levels, and
then chilled to release dormancy. Some seeds of each MC treatment were primed at 20°C for 2 days following chilling, after
which all seeds were evaluated in laboratory tests and a nursery trial. Germination potential of the FI seeds declined in
the lab tests by the second test date, which was reflected in low seedling emergence in the nursery in birch. The primed FI
seeds of alder germinated most rapidly in the nursery, but other effects were not significant. Seedling emergence was better
in the nursery in response to the TMC than the FI pretreatment in birch.
相似文献
Conor O’ReillyEmail: |
11.
The tissue culture of Schloss Mannheim(Rosa Chinensis var.Flaribunda) with full and unsprouting bud of stem segments as the explants was experimented. The result shows that the buds sprouted
best on MS medium with the addition of 6-BA 1.0 mg/L, and differentiation was best on MS medium with addition of 6-BA 1.5
+ NAA 0.05 + ZT 0.1 mg/L or KT 1.0 + NAA0.05 + ZT 0.1 mg/L. The MS medium with addition of 6-BA 0.3 + NAA 0.0 5+ ZT 0.1 mg/L
or KT 0.3 + NAA0.05 + ZT 0.1 mg/L showed a good result for developing strong shoots. 1/2 MS medium with the addition of IBA
0.1 mg/L or IBA 0.1 + NAA 0.02 mg/L had best result for rooting. The plantlets should be transplanted from test-tube to soil
when they grew to 2.5 ∼ 4.0 cm high and have 3 ∼ 5 strips short roots. A higher survival rate was obtained under the conditions
of controlling humidity and temperature. 相似文献
12.
A new isoflavone glucoside (1) was isolated from the roots of Astragalus membranaceus var. mongholicus. Its structure was elucidated by spectroscopic methods. 相似文献
13.
Garcinia kola is highly used as chew-stick for dental care in West Africa, but it is nearly commercially extinct in nature. To help find methods to increase rate and percentage of germination, we investigated its seed germination responses by using several collections and pre-treatments. Seeds processed from 6-week old green fruits did not germinate, whilst those of 10-week old partly-mature, at the intermediate stage through full development, germinated 46%. Seeds from orange mature fruits reached maximum 54–62% germination. Radicles emerged 6 weeks after sowing and normal germination with emergence of the primary single shoot growth occurred after 12 weeks. There was no significant difference (P ≥ 0.05) between germination responses of seeds from Ghana and Cote d’Ivoire. Seeds did not germinate when dried to below ca. 30% MC. De-coating seeds or soaking intact seeds in a 70% ethanol solution increased germination to 82–92%, and also increased germination rate; however germination was not uniform. Because difficulties in germinating these seeds stem from the physical presence of the seed coats and the slow growth of the embryos contained therein, we recommend that fresh seeds from mature fruits be de-coated and immediately sown in preferably, an aerated medium (e.g., sawdust) for cultivation. 相似文献
14.
To demonstrate the seed dormancy and germination characters of Robinia pseudoacacia L., an exotic tall tree species in Japan, we applied scarification, cold stratification, diurnal thermal regime, heat shock,
and/or winter weathering treatments to the seeds. These characters differed markedly among three seed sources (Trees K, B,
and I). Scarification revealed that most seeds from Tree K showed physical dormancy, whereas those from Tree B had no physical
dormancy. The seeds from Tree I showed weak physical dormancy so that the seeds eventually germinate without any treatments
as time goes by. The physical dormancy in Tree K was broken by a long, high heat shock treatment. The results imply that seeds
from Tree K respond to fire in natural conditions. Seeds from Tree I responded to a wide range of thermal regimes, except
for long, high heat shock. In contrast, most seeds from Tree B absorbed water during cold stratification and some germinated.
However, many seeds from Tree B died in the soil during the winter, presumably because of microbial and fungal infections.
Seeds from Trees I and B acquired physical dormancy by weathering during the winter, implying that seedpods that remain in
the crown function as an aerial seed bank. R. pseudoacacia may be able to produce various levels in dormancy with respect to the winter condition. 相似文献
15.
Variations in seed germination of Hippophae salicifolia with different presoaking treatments 总被引:1,自引:0,他引:1
Mature seeds of H. salicifolia, collected from five provenances (i.e. Hanuman Chatti, Helang, Lata, Rambara and Janggal Chatti) in west Himalaya, India,
were treated with stratification (at 4°C for 15, 30 and 60 days) and in different concentrations of GA3 (5, 10, 20 mM), KNO3 (50, 100, 200 mM) and Thiourea (50, 100, 200 mM) solution to determine the variations in seed germination. Results reveal
that the germination rates of seeds from different provenances under different pre-sowing treatments are significantly increased
compared to those in control (24%–30%). The seeds treated with Thiourea (100 mM) have highest germination rate (76%–83% for
different seed sources), followed by those (63%–71% for different seed sources) pretreated with stratification (4°C, 30 days).
GA3 treatment significantly shortens the mean germination time (MGT) and improves seed germination percentage. Considering
the practical applicability and cost effectiveness, thiourea (100 mM) and stratification (at 4°C) treatments for seed germination
are recommended for mass multiplication through seeds of H. salicifolia in village/forest nurseries of the west Himalaya, India. 相似文献
16.
Changbai pine (Pinus sylvestris var.Sylvestriformis) is an endemic and important tree species in Changbai Mountain. There were only 63 plant species in Changbai pine plantation,
where hemicryptophyte was dominant(39.68%). Simpson diversity index was 0.87, Shannon-Wiener diversity index was 2.96, and
evenness index was 0.82. Community structure were divided into three layers: tree layer, shrub layer and herb layer. The total
biomass and net production were 111.982 t/hm2 and 8942.80 kg/(hm2 a) respectively. The total biomass for tree, shrub and herb layers were 106.150, 2.230, 2.264 t/hm2, accounting for 94.79%, 1.99%, and 2.02%, respectively, and net production for those were 7465, 223, and 1182 kg/(hm2 a), accounting for 83.47%, 2.49%, and 13.22% of the total respectively. The nutrient content in various organs is in the
order of needle> branch> root> bark> trunk, For the assimilated organ, the nutrient content is in the order of N> K> Ca> P>
Mg, and that in absorption organ is in the order of Ca> N> K> P> Mg. For the whole plantation ecosystem, nutrient content
is in the order of soil> litter> herb layer> shrub layer> tree layer. Nutrient storage and its accumulation rate in tree layer
take up 88.79% and 76.43% of the total, respectively.
The project is funded by the Opened Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences
Responsible Editor: Chai Ruihai 相似文献
17.
Comparative study on drought resistance ofLarix olgensis Henry andPinus sylvestris var.mongolica (I)
Water potential (ϕ w) and net photosynthetic rate (Pn) ofLarix olgensis andPinus. sylvestris var.mongolica decreased with the decrease of soil water content. ϕ w and Pn ofL. olgensis changed hardly during the first 9 days after stopping watering, then decreased sharply at the 10th day Pn ofP. sylvestris varmongolica decreased slightly during the first 8 days, then decreased sharply at the 9th day. Their respiration rate, chlorophyll content
and their a/b ratio changed hardly. The following 3 conclusions were obtained and discussed exhaustively. (1) ϕ w can be used
to direct watering as a sensitive index of judging whetherL. olgensis andP. sylvestris var.mongolica lacking water. (2) The decrease of Pn ofL. olgensis andP. sylvestris var.mongolica when drought had nothing to do with chlorophyll. (3)P. sylvestris var.mongolica had morphological drought resistance, while Lolgensis had physiological drought resistance, and their drought resistance was discussed comparatively first time. 相似文献
18.
The biomass and net primary production of Mongolian scotch pine (Pinus sylvestris L. var.mongolica) plantations of west Kerqin sandy land were measured. According to average standard trees, the biomass, net primary production
and their distributions of trunk, bark, branch, leaf and root of 16-year-old stand were analyzed. The regressive equation
for the estimation of each organ biomass was established through dimensional analysis. Preferable equation with higher precision
was selected. The study results showed that the total biomass of the forest community was 62.023 t/hm2 and net primary production was 5.045 t/(hm2·a), which indicates that the community of plantation possesses high bio-productivity.
(Responsible Editor: Chai Ruihai) 相似文献
19.
The isolation of a new flavan, 5,7,4'-trihydroxy-8-ethoxycarbonylflavan (1), from the root of Daphne odora var. atrocaulis is reported. 相似文献
20.
Reddy KD Rao BV Babu GS Kumar BR Braca A Vassallo A De Tommasi N Rao GV Rao AV 《Fitoterapia》2011,82(7):1039-1043
Phytochemical investigation of Caralluma adscendens var. gracilis and Caralluma pauciflora (Asclepiadaceae) whole plant extracts allowed to isolate one pregnane glycoside and two pregnanes characterized as 12β,20-O-dibenzoyl-5α,6-dihydrosarcostin β-oleandropyranosyl-(1→4)-β-cymaropyranosyl-(1→4)-β-digitoxypyranosyl-(1→4)-β-cymaropyranosyl-(1→4)-β-cymaropyranoside (1), 12β-O-benzoyl-3β,11α,14β,20R-pentahydroxy-pregn-5-ene (2), and 11α-O-benzoyl-3β,12β,14β,20R-pentahydroxy-pregn-5-ene (3), respectively. Their structural characterization was obtained on the basis of extensive NMR spectral studies. Three known pregnane glycosides along with lupeol and β-sitosterol were also isolated and characterized. 相似文献