Abstract:The fine structures of merozoites and gametocytes of Leucocytozoon caulleryi from peripheral blood, liver, spleen and othef tissues of naturaliy infected chickens were examined under electron microscope. Results revealed that:The merozoites of Leucocytozoon caulleryi appeared to be round to oval in shape and were surrounded by two clearly marked membrances, i.e.a thin outer and a thick inner membrane. The merozoites possessed a large round to oval nucleus, a small nucleolus, numerous ribosomes,a mitochondria with tubular cristae and 1 - 2 large lipid inclusions. The micro- and macro-gametocytes were surrounded by 3-layered clearly marked membrane as in Leucocytozoon sabrazesi but in the mature gametocytes of L. caulleryi only 2-layered membrances were seen. The mature gametocytes were round or elliptical in shape and contained a nucleus, numerous ribosomes, food vacueles, lipid inclusions and endoplasmic reticulum in the cytoplasm. The microgametocytes were smaller than macroga-metocytes and possessed a large nucleus. The macrogametocytes were also easily distinguished from microgametocytes by their dark staining appearance and their well developed endoplasmic reticulum.

Abstract:In this article the organization of the vegetable market in Hong Kong had been decribed. The function of the organiztion was evaluated according to four proposed criteria. Economic analysis were made in three aspects,viz. 1. the pattern of supply and demand of vegetables in Hong Kong; 2. the origin of imported vegetables; 3. the price of the vegetables imported. Preliminary analysis showed that the vegetables from inland China occupied the major portion of the vegetable market in Hong kong. But due to the relative low quality of the Ciine;e vegetables they have been gradually squeezed out of the Hong Kong market by vegetables imported from overseas. The reasons for this has been analysed. In our viev if we are to increase the comoetiveness of our vegetables in Hong Kong and retake the deprived portion of the Hong Kong market that has been encroached by foreign vegetables then it is important that we should improve upon the method of production and circulation of our vegetables for export and also restructure some of our foreign, trade practices and policies.

Abstract:By means of chromosome Giemsa-C banding and polyacrylamide gel electrophoresis of pcroxidase isozymes, four clones derived from Saccharum arundinaceum Retz. and their parents were analysed to identify the hybrids. The main results were as follow,1 . Among 60 chromosomes of S.arundinaceum,56 were characterized by the present of telomerlc bands, while only 2 or 4 of such chromosomes were detected in one cell of the sugarcane varieties. The differences of C-banding pattern between the male and female parents were significant.2. Clones Ya Cheng 73/07 and Ya Cheng 75/283 were true hybrids as they showed intermediate characters between the two parents both in chromosome C-banding pattern and peroxidase zymogrom. The other two, Ya Cheng 57/25 and Ya Cheng 73/512 were obviously closed to their female parents respectively.The value and behaviour of S. arundinaceum in sugarcane breeding was estimated onthe basis of chromosome C-banding patterns, and the advantage and limit of the threemethods used in identificating of hybrids were discussed.

Abstract:The parameters, a . b . c, of Weibull equation were calculated by using data of development of groundnut rust accurring in many years. Stepwise multiple regression analysis showed that the location parameter a and the scale parameter b can be calculated by the number of days for disease to reach at 0.5, 1, 5, 10% and the time intervals of two points among these ones. The shape parameter c can be calculated by the data (time and disease) of the four points and parameters a and b with the weibull equation. According to parameters a, b and c, disease development can be calculated with Weibull model and, if continuing on making investigation of disease development , we can use more data to estimate the parameter c and thus make the forecasting more accurate.

Abstract:Two virus isolates were obtained from the passion fruit plants growing in the campus fruit garden of South China Agricultural University. The two isolates were found to be identical, and was therefore suggested to be an if elate cf (MV cr basis of the morphology of the virus particle, serology, host range, differential host reaction, physical properties and aphid vectors . Peanut was found to be a new artificial inoculated host plant of CMV which induced local lesions on inoculated leaves.

Abstract:This article outlines a rapid simple and reliable method for diagnosing citrus yellow shoot (YS) it was named "direct fluorescence detection method" . Thin leaf section were prepared from fresh tissues of YS-lnfected and healthy citrus plants, when observed under a fluorescence microscope (Type, Olympus AH-FL-2), a yellow fluorescence was distinctly observed in the YS-infected phloem tissues and not in the phloem tissuses of healthy plants and of those infected with tristeza, exocortis, canker, scab, greasy spot, Mg and Za deficiency.

Abstract:Experiments indicated that the assimilatory branch swelling of Casuarina in coastal areas of Guangdong province was caused by salt injury. Sodium choride and potassium chloride were the main causal agents.The underground parts of Casuarina plants were more tolerant to salt injury than the aerial parts.Chemical analysis of the assimilatory branch samples collected from the coastal plants showed that the contents of chloride ion and sodium ion in the diseased assimilatory branches were 2 times as much as in the healthy ones.Analysis of soil samples taken from the coastal areas showed that the salt injury of Casuarina trees was in relation to the salt content, the amount of organic matter, moisture , and the pH value in the site where the trees had been growing. Experiments also demonstraed the effect of the soil moisture and soil texture on the salt injury of Casuarina,A clonal variation in salt tolerance is apparent. Of 15 clones tested only one was highly tolerant.

Abstract:This paper gives a critical review of toosendanin, including its source, isolation, physical and chemical properties,industrial production, toxicology to vertebrates and insects, with special emphasis on the potential of development as a novel class of botanical insecticides. As far as the authors are aware, the chinaberry tree Melia toosendan Sieb. et Zucc. is mainly found in China and toosendanin was first isolated in China .We are the first group working on toosendanin as an insecticide. The unique properties of the toxic principles of toosendanin as an antifeedant, systemic and stomach poison as well as insect growth regulators, local availability, safe to the environment and com, patibility with the agroecosystem emphasize its ample potential in insect pest management system.