Abstract:A two-year greenhouse pot experiment was carried out by planting rice with 15N labeled fertilizers, urea, KNO3 and leguminous green manure (vetch) . The results are as follows1. Application of inorganic fertilizers in flooded soil (1986), whether urea or KNO3, led to increase of soil-N uptake by rice, the percentage increase over the control were 3.4-12.7 or 13.0-28.9 respectively when applying KNO3 or urea. For such effect, (1) Urea was superior to KNO3; (2) Deeper mixed application of each fertilizer was also correspondingly superior to the two surface placements done with each fertilizer.2. Rice plant-N derived from soil, which continuously increased throuthout the whole growth period, was 21. 9% to 31.0% (urea) and 26. 4 % to 40. 8% (vetch) from the six-leaf tu the fully mature period.3. As to increasing soil-N uptake by rice,vetch material performed better than urea,while the total soil-N uptake by rice with application of urea or ground vetch material was higher than that of the unfertilized control during the whole growing season of 1987.4. Whether chemical N fertilizers were applied or not, or no matter what forms of chemical N were applied, loss of original soil-N inevitably occurred when planting rice in flooded soil. The proper application of organic fertilizers was favourable to the maintenance of original soil-N, as well as the increase of soil fertility.

Abstract:By means of life tables and the index of population control(IPC) ,rice varielal resistance to the brown planthopper(BPH),Nilaparvata lugens (Stal)was studied in the paddy field. Varieties "Xinghuizhan 1" and "7915 "were indentified as highly resistant (HR ), "Qiguizao 25 "and "Bohuizhan 1" as moderately resistant (MR) ,and"Shuanggui 1 "as susceptible(S)to BPH.The results of the studies in paddy field and the green house showed that the fecundity and survival rate of the pest were markedly affected by the resistance of the rice varieties. Because the IPC value of rice varieties was a comprehensive reflection of the influence of the varieties on the insect pest population, the index of population control (IPC) could be an important parameter in identifying varietal resistance.

Abstract:This paper reports the use of state space analysis and the optimal controlling theory to set up an optimal controlling model for adjusting age class in forest management, and gives examples in using mathematical programming to solve problems.

Abstract:This paper deals with studies on the similarity of the athropod communities in paddy fields located in different habitats and their cluster analysis by using the data obtained from both Yangjing County, Guangdong Province and the suburban districts of Fuzhou, Fujian Province. The formula of Eculidean distance was used to measure the similarity index between the different communities. The results showed that the structure of the communities in the different habitats of the same district were basically similar. It could be shown that there were some differences in the commmunities betweeen Yangjiang and Fuzhou by comparing the similarity indices. The cluster analysis indicated that the communities in different habitats could be clustered at larger values of the similarity index and could provide farmers with references for 1PM.

Abstract:This paper describes a successful transplantation of the silkworm at the pupal stage. The biological effect after the implantation of the ovary into the male pupa was investigated, and the period during which transferance of vitellogenin to the ovary via the blood occurred was identified as the pupal stage. The result of the experiment was as follows; for the 2-hr aged male and female pupa, it was most suitable to do the transplantaton after low temperature treatment of the pupae; after the ovary was implanted into the male pupa, the rcipient developed very well, the rate of emergence reaching 82. 5 % - 1 00%, Mature eggs formed inside the ovary of the male pupa, though there were some changes in size, weight, protein content, nuclec acid content and ultrastructure of the eggs. After parthenogenesis treatment, 14. 2% -16. 8% of the eggs inside the male pupa developed into early embryos and it should be possible to have progenies if further study is conducted.

Abstract:从甜橙、蕉柑和化州橙的病树上取具有典型黄龙病症状的芽条,分别用不同温度的1000ppm盐酸四环素溶液处理一定时间。试验结果表明:用44,46,48和50℃处理15min,45℃处理10,20和25min,47℃处理10和20min,49,50和51℃处理10min的病芽条,嫁接于无病红桔实生苗上,经连续3年观察,均未见发病。而用20℃1000ppm盐酸四环素溶液浸20min或20℃清水浸15和20min,以及分别用44,45,46和47℃热水处理15min,则有31.1％～95.1％的植株发病。柑桔芽条用45～48℃的四环素溶液处理10～15min,既保证治疗效果,又有较高的成活率,可在生产上推广应用。

Abstract:采用高温增繁饲料添加剂、人工授精和人工辅助自然交配、改善营养水平和环境条件、选留耐高温种用公兔等项综合措施,使毛用家兔在高温季节保持正常繁殖水平。两年试验结果:母兔受胎率为89.3％,母兔产仔率为98.7％,断奶仔兔成活率为84.2％,适繁母兔能在34℃配上种,36℃顺产。

Abstract:The chromosomes of pollem mother cells of the sweet orange (Citrus Sinensis L. ) exhibited translocation,inversion and a synapsis during meiosis after irradiation treatment. These chromosomeal mutations and abortion in the pollen mother cells resulted in decreased fertility and the production of seedless or commercially seedless fruits. Statistical analysis of the data indicated that there was marked inverse relation between the frequency of ceiis with chromosomal mutation and number of seeds in fruit;and marked positive correlation between germinative rate of pollen and number of seeds in fruit. Of all the chromosomal aberrations, the appearance of asynapitc univalent and resultant pollen abortion was the major cause of seedless fruits.

Abstract:Rice varieties having a moderate level of resistance (MR) to the brown planthopper (BPH), Nilaparvala lugens, were studied to determine the mechanisms of resistance. The resistance in MR rice varieties was due to a combination of strong tolerance and a certain degree of antibiosis, but the resistant varieties generally had a high level of antibiosis and nonpreference. The number of feeding marks produced by the proboscis of BPH on the MR rice varieties was significantly less than that on the resistant varieties, indicating that the feeding frequency of BPH on the MR varieties was lower. The results showed that the BPH caged on the resistant variety ingested less food consequently the plants suffered slight injury from BPH. The resistant variety Mutlgo had the lowest functional plant loss index (FPLI) and percentage of yield loss compared to the MR and susceptible varieties. The MR varieties such as Zhong shanhong and Baoxuan 2 had a stronger compensatory ability in comparison with the susceptible variety TN,when they were injured by BPH with the same level of population, as demonstrated by the fact that the MR varieties had lower FPLI, higher level of photosynthetic activity and yield. The BPH fed on the MR varieties had lower value of food metabolic utilization than those on the susceptible variety TN1, although among them there were no distinct differences in quantity of food ingested and honeydew excreted. In all varieties tested, the respiratory intensity of the injured plants was significantly lower than that of the healthy ones. But the injured plants of the Mudgo variety had a greater decrease of respiratory intensity than those of other varieties.

Abstract:The Taxonomy of Fusarium solam is reviewed in this paper, including the developement of its taxonomy, the holomorph,classification of formae specialis and genetic basis. The authors consider that the name of the species to be Fvsarium solani (Mart. ) Sacc. ,that of the perfect stage Nectria haematococca Berk, et Br. , and that the classification of the formae specialis on the basis of mating type in conjunction with pathogenicity is acceptable.

Abstract:This paper reports the results of a study on the biology and chemical control of the rose sawfly,Arge pagana Panzer in 1982-1983.It is one of the most important pests of the rose. It was observed that in the field generations overlap. In the insectary ,there were one to nine generations each year in Guangzhou, Guangdong Province. Winter was passed as mature larvae within cocoons in the soil. The eggs were laid individually in two longitudinal rows, being inserted into a tender stem by means of the female' s strong saw-like ovipositor. The eggs hatched after 6. 0-12. 0 days. The larvae fed on the tender leaves and cause injury to the field-grown rose. When mature, the larvae descended to the ground and spun their cocoons in the soil. Reproduction is bisexual or parthenogenetic. The larva had five to six instars.and larval development lasted 8. 5-18. 0 days. For the pupa it was 8. 0- I 3. 5 days. The adults lived for 1. 5 - 9. 5 days.Laboratory studies showed that spraying with Dipterex, Dichlorphos, Phoxim, Malathion, Pyridaphention, Cymbush.Dimcthoate or Omethoate was very effective in the control of 2nd -4th instar larvae.

Abstract:This paper is a review of the Genus Castanopsis in Guangdong Province and Hainan Province. It comprises 24 species and 4 varieties. Among them there are 1 new species ( C. semifabri X. M. Chen et B. P, Yu) ,2 new varieties(C. hainanensis Men. var. litoralis X. M. Chen et B. P. Yu,C. chinensis Hance var. hainanica X.M.Chen et B. P. Yu) ,1 new name (Gsect. Fissae X. M. Chen et B. P. Yu) and 1 new recordation to Hainan (C. fargesii Franch. ). The evolutionary tendency of their morphological characters is summarized preliminarily .

Abstract:In accordance with the development of yield,the growth process of the sweet potato plant could be divded into three phases; 60, 60-90 and 90-150 days after planting were defined as early,middle and late growth stages respectively.The fresh and dry weights of vines reached the maximum amount in the early stage and decreased from then on. The fresh and dry weights of tubers increased slowly during the early stage and speeded up in the middle and late atages. Total biological yield,which was greatly affected by tuber weight,increased relatively faster in the late growth stage. The ratio of fresh weight to dry weight and the percentage of starch in tuber increased relatively faster and reached peak value in the middle growth stage. The accumulated yield and the content of soluble sugar in tubers increased mainly in the late stage.For the whole growth season the protein contents in organs of the sweet potato plant were ranked as follows:leaf blade>root>leaf- stalk>stem>tuber. The protein contents of the various organs began to decrease 30 days after planting, with the development of plant growth the main flow of protein movement shifted from the aerial parts to underground parts (tubers). The accumulated yield of protein had a linear increase in the early growth stage, remained relatively stable in the middle stage and increased slowly again in the late stage. There was a very significant positive correlation between the accumulated protein amount of tubers and the dry matter ratio, as well as between it and the dry weight and fresh weight of tuber.

Abstract:In this paper are described the breeding process, major characters as well as cultivation techniqve of the export grade tomato variety "RED ROSE"."RED ROSE" was systematically selected through six generations from a hybrid fruit acquired in Hong Kong The plants of this mew variety are determinate. The fruits which are oval,bright red in colour,about 70 grams in weight and with uniform size have firm flesh. The flesh of the fruit is 0. 6 - 0. 7 cm in thickness and low in water content. The fruits are resistant to bursting and cracking,can withstand 6. 7 kg/cm2pressore when ripe and show xcellent transport quality .After being transported one hundred kilometers, the ripe fruits could store for more than twenty days. This variety has excellent taste and is the predominant export grade tomato variety of Guangdong Province.