1997 Vol. 14, No. 4
The results showed that the water content of air-dried wood averaged 10.96%, ashy substance content 0.72%, hot-water extract content 4.03%, 1% sodium hydroxide extract content 15.92%, benzyl extract content 4.29%, lignin content 31.41%, and poly-pentose content 10.09%.
Using principal component analysis, the fast-growing clones with high and stable seed production, and great resistance of the filial generations were selected as materials of the first generation improved orchard, which obtained genetic gain of 150. 39%, adincreased the volume growth rate of the frecent generation by 33. 81%, and height growth rate of the filial generation by 8. 07%.
A study on postharvest physiology of chestnuts in 5 clones of Castanea mollissima shows that Chinese chestnut is a kind of climacteric nuts. Both respiration rate and activity of amylases gradually increase one week after the spined cupule is removed, with the latter reaching a peak later than the former. Differences in either respiration rate or enzyme activity are there among the clones. It 's suggested that theatments for fresh-keeping storage be finished within one week after removing the spined cupule is done.
A study on methods for germinated seed gragting in Chinese chestnut and on the effect of temperature for healing of graft union and nursery planting on raising of grafted seedlings showed that 82. 28% was contributed to by established seedlings from large germinated seeds on which seed root grafting was done, followed by promoting healing by keeping them in moist sand at certain temperature and later planting them in some protected area. The seedling was raised, gragted and sent out of the nursery in the same year with anaverage height of 54. 61 cm at tained. Those unsuccessfully grafted could also be used in autumn grafting.
A 8 hm2 stand of Chinese chestnut fruiting early with high yield was established in 1993. The yield for 4-year-old trees amounted to 12195. 2 kg hm- 2 on the average with effective technical measures taken, which is of significance to chestnut production.
The main reason for low survival rate of grafted Chinese chestnut on wild chestnuts lied in that the chits on parent stocks were not moved in time. All the wild chestnut trees with more than 1. 2 cm diameter at tree basis could be used as parent stocks.
The three-level artificial neural networks was applicated to study the law of oriented cultivation of Chinese fir stocky plants. The data of 36 groups were measured from sowing( A ), final seedling time ( B ) and final seedling number ( C ). The relation between ground diameter ( Y ) and A, B, C was analysed. Based on A, B, C, the ground diameter Y could be predicted.
The effect of different logging systems, such as the tractor skidding, cable yarding and chutting on forest soil, were analysed. The results showed that tractor skidding seriously affected the hardness, bulk density and macropore space of the soil and hindered growth of woods, the organic mat terw as reduced by 10. 4%, and that cable yarding created ditches and the macropore space and organic matter of soil in the main ditch were reduced by 3. 7% and 3. 614%, and that in all kinds of chutting, the effect of plastic chutting on the soil was least and the effct of soil chutting was largest. In order to reduce the disturbance of logging systems on the soil, some technical measures were gived.
The results showed that the adhesive rate did not affect MOR and MOE of the laminated bamboo boards. The adhesive rate significantly afacted TS in cool water and in boiling water, TS growed with the adhesive rate reducing.
Calycanthus chinensis is a tertiary relict species and is endemic in China with a very restricted natural distribution area. It is in immminene danger and has been listed in rare and endangered plants of second order by China. This article analyses the community distribution, flora, characteristics, structure and dynamics. The Calycanthus forest can be divided into two communities, namely: Cyclobalanopsis glauca-Caly canthus chinensis com. and Calycanthus chinensis shrub com. The former belongs to every green broad-leaved forest of subt ropical belt with more stability, and the latter is asecondary communty formed after dest ruction of forest vegetation. It is an instable one and tends to be Cyclobalanopsis glauca, Calycanthus chinensis com.
Orchidaceae plants in Mt. Tianmu included 24 genera and 35 species. Classificationand idex of the plants were mainly based on plant forms. The temperate zone compositions were dominating over the Orchidaceae plants in Mt. Tianmu.
There are 278 species of woody scantentes in the north-western areas of Fujian, belonging to 83 genera of 41 families, having more tropical components. There are more small families and single families and genera than large ones. The analysis of the common species shows that this area s flora is the most relative to Mount Dinghushan s of Guang dong, and then to Mount Shennong jia s of Hubei and Mount Huang shan sof Anhui.
In this study, a total of six investigation plots with different kinds of tourist resources were selected in the West Lake scenic resorts of Hangzhou. Within each investigation plot, the factors to affect tourist resources quality (TRQ) were divided into nineevaluation elements. The observers selected randomly were asked to give an scale for each evaluation elements, ranging from 0 to 10. Six linearreg ression models, using the TRQ as a dependent variable and evaluation elements as independent variables, were developed. The results indicated that the scenic plot called Three Towers Mirroring The Moon was the best place where tourist like to visit in the six investigation plots, and the water scenic beauty was the important factor to affect the tourist resources quality in the West Lake scenic resorts.
This paper introduces a recurrence formula for estimating the variances of errors of a sequence forecasted by an autoregression model and gives two examples under both smooth and nonsmooth conditions.
The green industry has been developed in China at present. This paper analyses its characteristics and claim. To push forward the rapid development of China s green industry, some countermeasures are put forward: to strengthen consciousness of environment protection, to do well industry program, to formulate industry policy, to organize business group and to train men for profession.
Land is the basic means of agricultural production. There are great potentials in land-developing in China s vast mountain and hill areas. But only those land-developing that produce good integral effect can raise China s sustainable agricultural development. The key to gain good integral effect of land-developing in mountain and hill areas is achieving comprehensive coordination in land use. And the basic measure for it is tightening up the scientific management to land-developing, so we raise some countermeasures and suggestions.
From an analysis of a large number of English abstracts from the published scientific and technological periodicals, obtained are their main language characteristics, which are as follows: passive voice and the third person are often used, and semi-technical words, simple present and simple past tense are usually used and soon. Meanwhile, the writing models of English abstract are discussed in this paper.
This article analyses the reasons of the abundance of college students informal little groups. It advances that teachers should streng then the building of students grass-roots unit and standardize the informal little groups.
The results of the organic extracts of Cornus of ficinal is stone were directly added on maize starch adhesive and cassava starch adhesive showed that the extracts had a function that prevents the starch adhesives from mildewing and promotes stability of the starch adhesives. The midew proof power basically was a linear relation with adding volume of the extracts. And the extracts was notvery obvious on the water resistance of the starch adhisives.
The results showed that there were flavonoid, glucide, amino acids and anthraquinone in the extracts from leaves of Phyllostachys praecox and Ph. prominens. By anthrano nesulphuric acid method, the contents of water-soluble sugars in cool water extracts averaged 2. 64% in Phyllostachys praecox and 2. 99% in Ph .prominens, while in hot water extracts, the content saveraged 7. 10% and 6. 92% respectively. The nitrogen content and protein content measured by Kjeldahl method averaged 2. 77% and 17. 37% in Ph. praecox leaves, and 2. 59% and 16. 12% in Ph. prominens leaves. The analysis of amino acids indicated that the content of glutamic acid in two kinds o f bamboo leaves was the highest.
According to the results of oven drying cones by fixed temperature oven, seed extraction and germinating test, the best drying temperature for pond pine cones was at 41-50℃. Seed extraction and germinating measurement were made after drying the cones for 32h using model IHT seed oven. The results indicated that germination rate was 88%, and germination viability was 67%. It could reducet reatment period of seeds.
With the data from Database of Chinese Science and Technology Periodical between 19891995, the documents on studying ginkgo ( Ginkgo biloba L. ) were analysed by the methods of document measurement. And the age distribution, subject distribution and periiodical dist ribution of studying ginkgo were inquired into. The present situation of domestic studying ginkgo was primarily concluded, and some suggestions were put forward.