Abstract:Experiments were conducted to study the fertility change in tbe photoperiod-sensitive genic male sterile rice, Nongken 58 photoperiod-sensitive sterile line (abbr. Nongken 58S). under natural sunshine and different treatments of daylight length. The results revealed that Nongken 58S had two distinct periods of fertility change under natural condition in Guangzhou(23'08N) viz, the first ten days of June from fertility to sterility, the last ten days of August from sterility to fertility. Tbe change of fertility was a process of quantitative alteration to qualitative alteration. Tbe sterility was complete and stable in the sterile period,the fertility ,however, was rather variable in the fertile period. There were only sterile periods and semi- fertile periods in some years. The fertility of Nongken 58S was controlled by environmental factors during the development of the panicle. The panicle at different phase of development showed different sensitivity in the fertility change. Tbe most sensitive was the period from secondary rachis- branch and spikelet primordia to pollen mother cell formation stage. At these stages, the panicles induced by long daylight were completely sterile,but by short daylight, the more tbe days,the higher tbe fertility. The main factors causing fertility change were daylight length,the number of induction days and the temperature. The critical light length for tbe change from fertility to sterility was longer than that for the change from sterility to fertility,and they all shortened with higher temperatures. The number of induction days mainly influenced the development of quantitative alterations into qualitative alterations during the process of fertility change.

Abstract:There have been found 5 species of injurious mites in the mulberry plantations of Guangdong Province, (?) (Banks) and (?) Andre being the major onsis The changes in the water, ptotein and total amino adds content in the mulberry leaves attacked by (?) lation (Banks) are first reported in this paper. The absolute levels of the above-mentioned substances of the attacked leaves were greatly decreased, and thus the sericultural productivity was seriously affected. As to the studies on the control of both of the injurious mites in mulberry plantations in terms of harvesting methods and chemical measures, the top-clipping harvesting methods and the ordinary leaf-harvesting method had a different effect on the population density of the mites in the field;in respect to the depression ratio of the population and population trend index (I) value,in the assessment of the efficacy of several kinds of insecticides upon (?) (Banks), the results showed that lime sulphur mixture and Proparsits wen both effective in controlling the mites with low toodcity so the silkworms; they can be popularized in mulberry plantations.

Abstract:In this study,the average cortical evoked potential elicited by stimulating selectively tbe C-fibers (C-CEP) in the sapbenous nerve was taken as an index to reflect stow pain in order to observe the analgesic effect of He-Ne laser acupuncture. The results were as follows:1. Experiments carried out on 20 cats showed that both 1. 5 mW (irradiating distance 5 cm ,spot diameter 1. 5 mm,power density 84. 93 mW/cm2) and 15 mW(irradiating distance 10 cm ,spot diameter 2 mm,power density 477.71 mW/cm2) He-Ne laser irradiation on the median nerve inhibited very markedly the C-CEP.This suggested that laser acupuncture could inhibit slow pain.2. Intravenous injection of naloxone(0. 4 mg/kg) was able to reverse tbe inhibitory effect (on the C-CEP) caused by He-Ne laser acupuncture. This result indicated that the inhibitory effect of laser acupuncture analgesia was related to the activity of opiate-like substances(OLS).3. The induction period and tbe after effect of analgesia resembling those observed clinically in electro-acupuncture were also found in He-Ne laser acupuncture. In addition,in higher output power He-Ne laser (15 mW) irradiation in cats, two phases of inhibitory effect on the C-CEP were observed : the inhibition occurred firstly (1st phase) during and for a short duration immediately after tbe cessation of laser acupuncture, and then recurred (2nd phase) from the 3rd to the 20th min. after the cessation of laser Irradiation.4. From tbe results presented,it appeared that the effectiveness of He -Ne laser analgesia and tbe irradiated dosage of laser (i. e. tbe energy density denoted by j/ cm2) are,within certain limits, positively correlated.

Abstract:The mechanism of increased yield and sucrose content of sugarcane sprayed with rare earth (RE) solution was studied by means of pot experiments and field production experiments. The results showed that RE could increase the chlorophyll content and improve the ultrastructure of leaves and increase the number of grana and grana lamellae in the chloroplasts. So. it could increase the area of the photosynthetic membranes and the photosynthesis rate of the sugarcane. It could increase the activity of roots and promote the absorption of more N. P and K. and enhance nutrition metabolism. Sugarcane sprayed with RE solution had high levels of K. Ca. Zn. Cu and relatively low levels of Mn and Na. RE might regulate cane growth by regulating the balance of nutrient elements in the sugarcane.Tbe activity of acid and neutral invertases was raised in the stem elongation stage. But in the maturity stage, the activity of acid invertase was lowered while the activity of neutral invertase still remained very high. The sugarcane sprayed with RE solution grew quickly in the elongation stage and slowed down in the mature period to accumulate sucrose. RE could raise the drought resistance of sugarcane by maintaining the structure and function of the plasmolemma. controlling the osmotic pressure of cells and raising the plasticity of cell walls. It could also raise the salt tolerance of sugarcane by improving the permeability and the selective absorption of the plasmolemma. thus decreasing the harm due to high Na + content.

Abstract:Two new species of the genus Pseudocercospora . i. e. Pseudocercospora alpiniae S. Q. Chen et P. K. Chi and P. alpinicola S. Q. Chen et P. K. Chi causing leaf spot of Alpinia officinarum Hance are described respectively. Type specimens are deposited in the Department of Plant Protection. South China Agricultural University. Guangdong. China.

Abstract:本文分别以科、(?)、种为基本单位详细分析了观音山植物区系成分的组成特点。并通过与其它区系的比较,阐明了它在华南植物区系中的地位,探讨了它可能的起源及归属问题。

Abstract:In this paper are reported the results of a diagnostic survey conducted on 112 adult layer chickens from a flock in which osteopathic leukosis (osteopetrosis) was occurring. Only 3 positive cases were detected on the basis of clinical signs,but on first attempt 45 positive cases were discovered by radiography of one hind limb. This represented a 16- fold increase in detection rate and revealed the incidence of the disease to be as high as 46. 39%(45/97). In the positive cases,lesions occurred in 100% of the tibiae examined whereas only 24. 44% of the metatarsi showed pathological changes. Measurements of tibial external diameter and bony cortex on radiographs of hind limbs from 97 chickens,showed that in 52 osteopetrosis-negative chickens,the mid -portion of the tibia had a normal average value of 6. 16 mm (5. 5-7. 0 mm) ,and that the normal average value for the thickness of the cortical osseous tissue was 0. 64 mm (0. 4 - 0. 9 mm). Of the 42 occult cases which accounted for 93. 33% of the 45 osteopetrosis-positive birds,the external diameter of the bone fell within normal values,but the average thickness of the cortical bone was 0. 81 mm (slight increase) and 2. 12 mm (moderate increase). In the 3 clinical cases which occupied 6. 67% of the affected chickens,the external diameter of the tibia exceeded 7. 5 mm,attaining even 14 mm,while the thickness of the cortical bone exceeded 1. 5 mm,reaching even 9 mm.

Abstract:The author was able to raise soil temperature, preserve soil water, maintain soil structure, control weeds effectively, keep plant growing thrivingly and save labour when growing sweet potato in autumn with a minimum tillage cultivation technique in which the ground was covered with plastic films after the soil had been treated with weedkiller before planting. As a result,the yield of tuber and the total weight of sweet potao plant increased significantly and a good economic benefit was achieved.In another trial,control of weeds,saving of labour and increase in labour efficiency could be achieved by only applying herbicides. However,no significant yield difference between manual weeding and herbicide application was shown.

Abstract:Based on the pathological anatomy of infected phyllodes of Acacia cnariculiformis,it was demonstrated that the pathogens,Oidium sp. ,could directly invade the tissues via. the epidermal cells,intercellular space or stomata, and assimilate nutrient by their haustoria. After inoculation tests the highly susceptible phyllodes showed death and deformity of epidermal cells and decrease and partial degradation of chloroplasts in the parenchyma of the leaves whereas highly resistant phyllodes showed only allergic necrosis in their epidermal cells. There was a correlation berween the thickness of the epidermal cell wall and its cuticule in the phyllode and disease resistance.

Abstract:In the present paper is reported study on the wood of 9 genera including 26 species of Lauroceae in Guangdong Province.The ages of the wood becoming mature are shown by the variations in their fibre lengths. The results indicated that the maturing ages of wood of Lauraceas varied from 18 to 45 years in Guangdong Province which includes both subtropical area and the northern edge of the tropics. Within genus, the maturing ages were the same or similar among species,showing inherent intrageneric similarity.The wood structures of these 9 genera were compared and their systematic relationships discussed. It seemed that the relation between Beilschmiedia and Cryptocarya was much more closer than other genera according to their general wood structure,geographic distribution as well as their abundance of axial parenchyma. It is probable that Cryptocarya was derived from Perseeae as deduced by the increasing of axial parenchyma. Judging from wood anatomical structure,the laurel family formed a natural taxonomical group with no obvious distinction among the genera.

Abstract:In this paper, the biomass, content and distribution of the major nutrient elements (N, P, K, Ca, Mg) during the period of one year in young pure stands of Cunninghamia lanceolate and young mixed-stands of Cunninghamia lanceolata and Michelia macclurei were investigated. The result showed that the content of nutrient elements in the five-year stand was higher than that of the other age-groups (7-8, 10-2020-30yr. ) stands, except the Ca. The requirements for nutrient elements in both species were the same, being N > K Ca>Mg>P, but the relative rpquirement for Michelia macchtrei was lower than that of Cunninghamia lanceolata, except the Mg.