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991.
A micropropagation method for Jaal (Salvadora persica)—a tree of arid horticulture and forestry has been developed. Nodal segments of fresh shoot sprouts originated from axillary
buds obtained from a plant around 35–40 years old lopped plant were used as explants for establishment of in vitro cultures.
Surface-sterilized explants produced optimum number of shoots through activation of axillary buds on Murashige and Skoog’s
(MS) medium containing 8.88 μM BA (6-benzyladenine) + additives (25 mgl−1 each of adenine sulphate, arginine, citric acid, 50 mgl−1 ascorbic acid). The shoot multiplication was influenced by the successive transfer of the mother explants for 4–5 passages.
The maximum number (23.1 ± 0.73 shoots per explant) of shoots were regenerated on MS supplemented with 1.11 μM BA + 1.16 μM
Kn (Kinetin) + 0.54 μM NAA (α-naphthalene acetic acid). About 90% shoots pulse-treated with a combination of 2460.27 μM Indole-3-butyric
acid (IBA) + 494.56 μM NOA (2-naphthoxy acetic acid) were rooted ex vitro on soilrite within 15–18 days. Over 80% cloned plantlets
were hardened successfully in a green house and transferred to polybag/pots. 相似文献
992.
Juan Valencia Chris Harwood Russell Washusen Andrew Morrow Matthew Wood Peter Volker 《Wood Science and Technology》2011,45(1):15-34
Peripheral longitudinal growth strain (LGS) was measured on a total of 81, 22-year-old pruned Eucalyptus nitens trees from five thinning treatments in a plantation thinning trial in Tasmania. Growth strain data were gathered at breast
height on each tree using the CIRAD-Forêt method. The effects of thinning treatment and tree diameter on LGS and its relationships
to solid-wood traits determined in a processing trial were examined. LGS was significantly higher in the direction of the
prevailing wind and was not significantly affected by either thinning treatment or tree diameter. An index of log end splitting
was positively related to tree diameter, sawlog position (upper/lower), and LGS, which explained up to an additional 20% of
the variance after tree diameter and log position were accounted for in a linear regression model. High LGS and log end splitting
were significant indicators of increased board end splitting. 相似文献
993.
R. S. Yadav B. L. Yadav B. R. Chhipa S. K. Dhyani Munna Ram 《Agroforestry Systems》2011,81(3):195-202
An investigation was carried out in an Entisol at farmers’ field in Jaipur district, Rajasthan, India during 2002–2004 to evaluate the effect of traditionally grown trees
on soil biological characteristics. Traditionally grown trees in farm lands for study consisted of Prosopis cineraria (L.), Dalbergia sissoo (Roxb.) ex DC, Acacia leucophloea (Roxb.) and Acacia nilotica (L.) Del. having a canopy diameter of 8 m. Results revealed significant and substantial improvement in soil biological activity
in terms of microbial biomass C, N and P, dehydrogenase and alkaline phosphatase activity under different tree based agroforestry
systems as compared to a no tree control (cropping alone). Soil microbial biomass C, N and P under agroforestry varied between
262–320, 32.1–42.4 and 11.6–15.6 μg g−1 soil, respectively, with corresponding microbial biomass C, N and P of 186, 23.2 and 8.4 μg g−1 soil under a no tree control. Fluxes of C, N and P through microbial biomass were also significantly higher in P. cineraria based land use system followed by D. sissoo, A. leucophloea and Acacia nilotica in comparison to a no tree control. Thus, it is concluded that agroforestry system at farmers’ field enhance soil biological
activity and amongst trees, P. cineraria based system brought maximum and significant improvement in soil biological activity. 相似文献
994.
The wood–adhesive interface was analyzed using five methods with the objective of quantitatively assessing penetration of adhesive into the porous wood network. Methods included fluorescence microscopy, scanning electron microscopy, backscatter electron imaging, wavelength dispersive spectroscopy, and X-ray microtomography (XMT). Each method provided a visual inspection, and all of the analysis methods were applied to the same field of view. XMT was the primary technique of interest. Rubidium hydroxide was used in place of sodium hydroxide in the formulation of phenol–formaldehyde adhesive. Rubidium was found to increase the X-ray attenuation of the adhesive. However, rubidium migrated beyond the adhesive interphase during specimen preparation, thus reducing its effectiveness for image contrast enhancement. The wood species studied included red oak (Quercus rubra), Douglas-fir (Pseudotsuga menziesii), and hybrid poplar (Populus deltoides × Populus trichocarpa). All techniques used for this study were useful, but each presented some limitations for bondline analysis. Despite the problem with rubidium migration, XMT for this application was promising. 相似文献
995.
Parklands are mixtures of trees and shrubs that farmers select for certain functions. In the Sahel, parklands are cultivated
together with staple food crops, such as millet and sorghum. Parkland trees are sources of foods, including fruits, fats,
oils, leafy vegetables, nuts and condiments that complement food crops in the local diet. Despite their socio-economic and
ecological role, many studies have shown that the parklands are degrading very rapidly. Therefore, there is a need to undertake
restoration actions that are based on a clear understanding of the livelihood context, such as the wealth status of the farmers,
in which these agroecosystems are evolving. Thus, we conducted a wealth survey with rural communities in two different farming
systems of Burkina Faso that are the cereal-based system in the “Plateau Central” and the cotton-based system in the “Boucle
du Mouhoun”. A total of twelve villages were sampled, six villages for each system. The Participatory Analysis of Poverty
and Livelihood Dynamics (PAPoLD) method was used by rural farmers to rank farmer households of their communities according
to their wealth status. The results revealed that 70% of households in the Plateau Central and 56% in the “Boucle du Mouhoun”
managed to escape poverty, and became wealthy. However, 2% of households of the villages in the Plateau Central and 6% in
“Boucle du Mouhoun” fell into poverty in the same period whereas 9 and 12% remained poor in these zones, respectively. The
main causes associated with households getting out of poverty are subsidies for cotton, external revenues from relatives working
in towns and gardening activities. Death of spouse, illness, high number of people in the household and indebtedness are the
main causes that lead into poverty. The implications of these findings in designing appropriate policies and management options
for a sustainable management of agroforestry parklands under different land use systems were finally discussed. 相似文献
996.
Keith E. Woeste 《林业研究》2011,22(3):353-359
Three kinds of plant growth regulators, gibberellinA 4/7 (GA 4/7 ), 6-benzylaminopurine (BA), and chlormequat chloride (CCC), were evaluated for their ability to promote strobilus and cone production in a Chinese pine (Pinus tabuliformis Carr.) clonal seed orchard. Treatments (0, 250, 500, or 1000 mg L -1 ) were applied during three periods (June- July, July-August and August-September) in 2005. Of the three plant growth regulators, GA 4/7 was the best for promoting flower and cone production. Trees sprayed... 相似文献
997.
Species diversity and stability of natural secondary communities in different layers with different cutting intensities 10
years later were investigated by calculating Marglef Richness index (R), Shannon-Wiener diversity index (H), Simpson diversity index (P), and Pielou Evenness index (J). Results show that the values of R, H and P among different layers are listed in a decreasing order: the shrub layer > the arbor layer > the herb layer, all the three
indices values reach the maximum under medium selective cutting intensity after 10 years. The J value of the shrub layer shows a concave parabolic change with the increase in cutting intensity; it shows a linear increase
for the arbor layer, whereas the J value of the herb layer shows an opposite change pattern. The values of R at different cutting intensities had high significant difference, but other indices had not significant difference. The stability
of communities at different cutting intensities after 10 years is non-cutting> low selective cutting intensity > medium selective
cutting intensity > high selective cutting intensity > extra-high intensity > clear cutting. The stability of communities
at different cutting intensities after 10 years shows that the greater cutting intensities, the worse the stability is. 相似文献
998.
Schizostachyum dullooa (Gamble) Majumder ‘dolu bamboo’ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India.
The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population
status and regeneration in Cachar tropical semi evergreen forest under private property resource management (PPRM) and common
property resource management (CPRM) regimes. Population status revealed current-year, one-year, two-year and three-year-old
culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent
in CPRM and population status was thus represented by current year (83%), one-year (16%) and two-year (1%) old culms. Net
change, rate of change and % gain in population for different age classes showed the prevalence of management practices under
CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and
59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term
economic and ecological sustainability of the species and alternative management protocols are needed for conservation of
the species. 相似文献
999.
TANG Fang . College of Forestry Resources Environment Nanjing Forestry University Nanjing China . Jiangsu Key Laboratory for Prevention Management of Invasive Specie Nanjing . ZHANG Xiu-bo LIU Yu-sheng College of Plant Protection Sh ong Agriculture University Tai’an China GAO Xi-wu Department of Entomology China Agricultural University Beijing China 《林业研究》2011,22(3):447-451
Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors. 相似文献
1000.
Md. Habibur Rahman Md. Abu Sayed Arfin Khan Bishwajit Roy Most. Jannatul Fardusi 《林业研究》2011,22(4):551-559
A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (a part of Sylhet Forest Division)
to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic
species. Data were collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots
of 2 m×2 m in size had 5 different habitat types of plants namely; forest, roadside, homestead (surrounding forest dwellers
house), fallow land and others (canals, streams and tea gardens side), which included a total of 55 regenerating species belonging
to 28 families. Meliaceae is the dominant family and shows the highest family importance value (26.3), having six species,
followed by Moraceae (24.24). Among the five habitat types, forest (43 species) possess the highest number of species, followed
by roadside (23 species). Total 15 exotic species among 9 families and 40 indigenous species with 24 families were recorded.
For exotic species, Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%). In case of indigenous species, Chickrassia tabularis possess the highest relative density (4.23%) and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia tabularis (10.8) had the highest IVI for exotic and indigenous species respectively. Different diversity indices such as Shanon-Winner
diversity index, species diversity index, species richness index, species evenness index, Simpson index and species dominance
index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levels of disturbance
was in the exotic species. Study suggests that proper protection from human disturbances and scientific management of natural
regeneration of two-study forests may lead a rich biodiversity site in the country. 相似文献