Owing to the generative propagation over a long period of time many lines of Camellia oleifera have varied and degenerated, which is the major factor resulting in low yield of Camellia production. For keeping the excellent properties of fine varieties it is of great importance to develop tissue culture and rapid propagation, using the organs, tissue and cells of elite trees. Since 1979 germination of embroids and pseudo-bulbils has been studied, and rapid propagation of axillary shoots tested, as a result, a number of plantlets from tissue culture of elite trees has been obtained. In 1982 a transplant experiment was established, and the surrival of plantation with such plantlets observed. The indices show the same growth of tissue culture plantlets as that of seedlings, in some cases the former is even better.

The present paper is dealing with the relationships between the growth of Pinus yunnanensis, of which stands were established by aerial sowing, and the soil conditions in the district of Liangshan, Sichuan Province, where there are many different types of soil such as mountainous laterite, sometimes in dark red colour, and yellowish red earth and brown earth and etc. Among those soils, mountainous laterite and yellowish red earth are more suitable for growing P. yunnanensis. Within the same type of soil there are some variations in depth, texture, pore size, amount of gravel and other physical characters by which the growth of the pine is significantly affected. The result of correlation analysis showed that,the growth of Pinus yunnanensis in height, diameter and volume was positively correlated with the depth of soil, and the pine stands growing on the loam contribute the greatest volumes compared with the other soils. It was also found that for this species the optimum bulk density was in 1.2—1.7g/cm³,porosity and gravel content around 36—55% and 10%, respectively.

The effects of O₃ and HF on ethylene release by some trees and shrubs are investigated. Some preliminary conclusions are as follows:1) When trees and shrubs were exposed to O₃ concentration higher than 0.25ppm, the ethylene release from plants of all species studied had increased remarkably before visible symptoms of injury appeared. Moreover, this production increased with increasing O₃ concentration. As plants were injured severely, ethylene release were decreased.2) The ethylene release in trees injured by HF increased remarkably.3) There was a close correlation between the abnormal abscission of leaf blades and the stress ethylene release or wound ethylene release Besides aerial pollution, the drought injury was the important factor causing the abnormal abscission of tree leaves, too.

Anoplophora nobilis Ganglbauer is one of the most important insect pests of poplar in Shannxi, Gansu Provinces and in Ningxia Hui Autonomous Region. The adults show slow action and have some regularity, acting by day and resting at night. There are two acting peaks during a day: one is about 10 a. m. the other 6 p. m. Their main actions are taking food, mating and laying eggs. The adults have weakly flying ability, usually only spread to and fro in the woods with the farthest distance within 1190m. Their action is mainly affected by temperature. Usually they act very well between 16.0℃ and 28.0℃, but the irregulary action can be observed when temperature is above 32.0℃ or below 10.0℃ The adults prefer to oviposit on the trunks with d. b. h. 7—12cm. The oviposition on the trunk rises with the tree age year by year within definite sizes of the trunk or branch. The adults show some specially preference to bite and oviposit on the cultivars of Section Aigeiros and Section Tacamahaca The different degrees in resistance were observed in Section Leuce to that pest. The insect also has definite choice to other tree species grown near villages, canals, road-sides, and buildings, paulownia and heaven tree appear to be more resistant to the pest. The adult mainly uses its antennae and labipalpi and other sense organs to accurately choose treespecies. Populus×dakuanensis has some chemical message matter that attracts the pest to bite and oviposit. Paulownia seems to have some repellency to the insect. The findings provide some theoretical basis for further study and control of this pest, specially for using insect resistant tree species.

The forest remains were unearthed at Chenghuang of Yehaizi in Mianning county, Sichuan Province. The specimens from the relict wood, fruits or cones, and leaves or needles have been identified, as well as the C¹⁴ age and the chemical and physical properties of wood determined. It follows from the results that the ancient forest, which existed in the area Yehaizi 6058±167 years ago, was a subtropical mixed forest composed of many coniferous and evergreen or deciduous broadleaved tree species. Also discussed are the burying and preservation of the forest and the survival of its remains, the succession of forest, and the changes in ecological environments.

The unsaponifiable matters of the oil from Xanthoceras sorbifolia Bge are separated by TLC with silica gel G into four fractions: sterols, 4-methylsterols, triterpene alcohols and hydrocarbons. The acetates of sterols are separated by TLC with 18% silver nitrate impregnated silica gel G, using CH₂CL₂-petroleum (7:3 v/v) as developing reagents. The identification of major components is carried out by TLC, m.p.,optical rotation, GLC, IR spectrum and MS or GC-MS.It is found that Δ⁷-stigmastenol, α-spinasterol and Δ⁷-avenasterol are present in large amounts in the unsaponifiable fraction, α-spinasterol (purity 99.5%),Δ⁷-stigmastenol (purity 99.5%) Δ^5.22-stigmasterol (purity over 98%) and Δ⁷-avenasterol (purity 98%) in the sterol fraction are isolated and identified, while trace Δ⁵-sterols as campesterol, β-sitosterol and cholesterol are identified only.

The unsaponifiable matters of the oil from Xanthoceras sorbifolia Bge. are separated by TLC with silica gel G into four fractions:sterols, triterpene alcohols, 4-methylsterols and hydrocarbons. The acetates of triterpene alcohols and 4-methylsterols are separated by TLC with 20% silver nitrate impregnated silica gel G, using CH₂CL₂-petroleum(8:2v/v) as developing reagents. The identification of major components is carried out by TLC, m. p., optical rotation, GLC, IR spectrum and MS. α-amyrin, taraxerol, tirucalla-7, 24-diennol and butyrospermol in the triterpene alcohol acetate fraction, cyclofontumienol and 4α-methylgorgostanol in 4-methylsterol fraction are isolated and identified. We find no evidence of the occurance of nonedibles in this oil.

The paper indicates the regularity of stress distribution over the sections of log grips by means of photoelastical method. It is concluded that the grips of vertical elliptical, circular and horizontal elliptical contour are stressed favourably. Under unfavourable work conditions a dangerous section forms on the inner wing of the joint between sprag and grip, where the stresses are concentrated. It is possible to determine the allowable gripping strenth of the grips made of various materials and of various section sizes, and furthermore, to design the gripping device with horizontal elliptical grips, using the data and formulae derived from the experiment.

Since 1974, the management of the nursery of scion for high-yielding cloues of Alcurites montana has been studied.We has set up many kinds of the nurseries of scion in Guangxi in 1981. They were the elite nursery, the centre nusery and the temporary nursery. It shows that they not only keep the pure lines of the clones but also produce a lot of fine scion in short term, in practice.Finally the paper introduces mainly the management of the nurseries of scion, such as, how to select the local of nurseries, the density for plant scion trees, the method for cutting scion, and have to raise the yield and the quality of the effectiye buds of the scion, etc.

Before fertilization spermatogonium of Taxodium ascendens Brongn has divided into two androgametes which are exactly in the same shape and size. Phenomena of fertilization take place in the middle of June with simple and cleavage polyembryony Most of the embryos developes. 6—7 cotyledons.

In this paper the structure, type, distribution, origin and development process of the blocked laticiferous canals in the bark of Rhus verniciflua Stokes are studued. These laticiferous canals are blocked with parenchyma cells alone or with both parenchyma cells and cork cells. These block cells are derivatives of the epithelial cells and the sheath cells. These cork cells are as form as storied cork. The block laticiferous canals may be divided into two main types:The homocellular block type and the heterocellular block type. The phenomenon of the obstructed laticiferou canal typifies a lacquer tree in age. And furthermore our study of the block laticiferous canals may provide some useful information for the theory of the structure of the laticiferou canal, systematicis of lacquer tree, regeneration of lacquer and the production of lacquer.

The paper discribes the labouratory experiment with tree leaves for measuring their disinfecting action on Tubercle bacilli. Tubes containing Tubercle bacilli were kept together with leaves of 20 tree species. The volatile substances secreted by leaves inhibit Tubercle bacilli through the medium of air. In comparison with the control the inhibiting effectiveness of almost all tree species accounts for 100%,that of Lagerstroemia indica L. was calculated to be 86%. The experiment also show that the inhibiting effect increases with the amount of leaves.It can be concluded tentatively that trees are closely related to people's health.

The present paper deals with the karyotype of Cryptomeria fortunei Hooibrenk ex Otto et Dietr. Results indicated that the chromosome of C. fortunei is 2n=22 with ten metacentric (M-type) pairs, one submetac-entric (SM-type) pair. The chromosomes (№g) in the genome showed a long kinetochore region containing several chromosomes, which may be regarded as characteristic of the karyotype of C. fortunei. Results also indicated that the key differential in the karyotype between C. fortunei and C. japonica.

A two-month survey of the natural enemies of the gypsy moth, Lymantria dispar (L.),in Beijing and the northeastern People's Republic of China confirmed the presence of 22 parasitic species in the genera, Hexamermis, Exorista, Carcelia, Parasetigena, Chetogena, Blepharipa, Elachertus, Anastatus, Tyndarichus, Rogas, Meteorus, Glyptapanteles, Cotesia, Apanteles, Phobocampe, Casinaria, Hyposoter, Campoletis, Ephialtes and 12 predatory species in Araneus, Harpactor, Epidaus, Picromerus, Dinorhynchus, Pinthaeus, Xylodrepa, Carabus, and Calosoma. Species diversity was greatest at Menjiagang, Heilongjiang Province, where the host population was moderate. Populations were low in 10 other collection sites. Nuclearpolyhedrosis virus (NPV) was moderately abuudant while the fungus Entomophthora aulicae occurred in some collected larvae and was evident in year-old cadavers, especially in Larix plantations at Dunhua, Jilin province. The most abundant parasites were the tachinids (5 species combined) and the gregarious braconid, Glyptapanteles liparidis.

Poplar mosaic virus is a new disease in China. The cultivar "Harvard" can be regarded as very susceptible to the virus. Use of infected plants can result in volume growth being 30% below normal.The results of trials in virus infection show that 1. The virus infects Vigna uaguiculata, Nicotiana tabacum, Cucumis sativus, Tropaeolum majus, Chenopodium foetidum, Ocimum basilicum and Petunid hybrida.The symptoms appeared in poplar leaf are light brown necrotic streaks. The symptoms of poplar leaf by inoculation are black-brown spots. The twelve clones of poplar are resistant, six clones are highly susceptible and two of them are moderately suscepit ble. 2. The dilutionend point is 10_-3, thermal inactivation point 75—80℃, longvity in vitro 7 days. 3. The measurement of the threall like virus particles is 672—735nm×12—13nm.