Abstract:A growth-model forecasting method is proposed to be a new method of plant disease forecasting, in which the field data obtained during the early period of the disease development are used to fit a mathematical model (growth-model) which is then used to forecast the disease development in the following period;more data obtained in the following period will be used to correct the parameters of the growth-model and further forecasting will be made again. In the present study, epidemiological data of 47 sets of 9 plant diseases caused by fungi, bacteria or viruses were used to validate the growth-model forecasting method and among all the 917 forecasting tests the mean degree of accuracy was 86%.

Abstract:The objective of this study was to determine the mode of inheritance of resistance to Fusarium wilt (Fusarium oxysporum f. sp. trancheiphlum) in yardlong bean (Vigna sesqupedalis (L) Fruhw. ) .Two Fusarium wilt resistant cultivars of yardlong bean, 'Zhuchang Dou' and 'Zhu Yan', were crossed in turn with two susceptible cultivars, 'Hong Zui Yan' and 'SI Gi Ching'. The F, generations of the crosses all showed resistance to the disease as identified by the inoculation with mixed spores of 5 isolates of F.oxysporum f .sp .tranchei-p'il'um that were collectel in the region of Guangzhou. Progeny of the F2 generations of all the corosses segregated in the ratio of 3 : 1 (resistant t suscepsible) , indicating that resistance is governed by a single dominant gene. The same ratio could be obtained whether a resistant cultivar or a susceptible cultivar was used as the maternal parent in the crosses, when theF, plants were backcrossed to the susceptible parents, the BC 1 population segregated in the ratio of 1 t 1 (resistant : susceptible) , but when they were backcrossed to the resistant parents, the BC 1 generations were entirely resistant. The results as shown by the F1 , F2 and the BC 1 generations demostrated that the resistance of 'Zhu Chang Dou' and 'Zhu Yan' to Fusarium wilt was governed respectively by one dominant gene.

Abstract:In a study of the rice mjcrospore, anthers from the same spikelet were used in the following methods of preparing anther squash slides: 1 ) fresh anther squash slides were prepared using distilled water, 2) fresh anther squash slides were prepared using aceto-carmine, 3 ) anthers were fixed in Carney's fluid for 24 hours and transferred to 70% ethyl alcohol for 15 minutes before being stained with aceto-carmine,and 4 )anthers were fixed in 3 % glutaraldehyde for 1 hour and rinsed twice with phosphate buffer before being stained with aceto-carmine.The experiment showed that contraction is not a normal feature of the microspore in its formative process but rather an effect of the fixatives on the young microspores. Hence, contraction could not be designated as part of the developmental stfge of the microspore, as reported in the literatures. Carncy's flujd caused Jess contraction at tetrad stage while glutaraldehyde showed less contraction at young microspore stage. No contracted microspores were observed in Treatment 1 when the squash slides were examined immediately. Plasmolysis occasionally appeared in some microspores in Treatment 2 .

Abstract:This paper is a preliminary nomenclatural principle on the specific Chinese name of Oryza L. . It includes 22 species Chinese name.

Abstract:This study deals with the mineral composition of every class of red earth, latcritic fed earth and latosol developed from granite in Guangdong Province by analyses of chemistry, X-ray diffraction, differential therm and electron microscope. According to the results of analyses,minerals of feldspar group are directly formed into halloysite and kao-linite and then kaolimte is transformed into gibbsite .Minerals of mica group are formed intogoethjte, hematite, 14A mineral and sericite. Plagioclase may change into sericite, and further into hydromica by depotassiumation. In the light of different compositions of primary and secondary minerals in the soil,it is suggested that the composition characteristics of soil minerals be affected not only by factors of soil formation that are dominated by zonality and bioclimatfc conditions, but also by complex reflection of all other factors of soil formation. Moreover, the neotectonic movement may also be one of the affecting factors .The intensity of weathering to minerals of latosol developed from granite in Hainan Island is not the strongest one in comparison with lateritic red earth and red earth. Whether it belongs to latosol needs further discussion.

Abstract:本文对广东西江地区不同立地不同龄组杉木人工林地上部分生物量和生产力作了研究,结果表明杉木林分生物量和生产力随立地条件不同而变化,3龄组Ⅰ、Ⅱ和Ⅲ立地地林分地上生物量和生产力分别为132.01、97.27和57.93吨/公顷及7.45、4.70和3.29吨/公顷·年。其中Ⅰ、Ⅱ立地间差异不显著,Ⅱ、Ⅲ立地间差异显著(P=0.05),Ⅰ、Ⅲ立地间差异极显著(P=0.01)。在相同立地条件下(Ⅰ立地)杉木林分生物量随着林龄增加而变化,3龄组分别为1、2龄组的3.44和1.6倍。其中3、1龄组间差异极显著(P=0.01),1、2龄组间差异显著(P=0.05),而2、3龄组间差异不显著。文章还对影响林分生长的栽植密度和环境因子作了讨论。

Abstract:This paper discusses and analyses the electro-chemical corrosion of 17-4PHMO (OCr17Ni 4Cu4MO2Nb) steel in 1.8% H2SO4acid and 4.5% Nad solution. The test revealed - that the sample steel under normal heat treatment in Cl- and H+ solution having a stable passive film on its surface can be punctured when its anodic potential is higher than 20mV. Due to a relative positive Epp value, self-passivating at the site of corrodent Pitting arising from the punctured passive film, the passive ' film will become perfec again. Besides the microscopic structure of this steel after heat treatment is described, the relationship between heat treatment and its electrochemical property is also shown in this paper. It is concluded that pitting corrosion of this steel is hot liable to appear in acid solution with higher content of NaCl.

Abstract:This paper presents a method of drying grain. It is using a method of grading automatical heating air flow in the low-temperature slow-velosity drying grain. Using this drying grain method,the air flow in the air duct of the drying machine may be in low or normal temperature automatically.But it always has the ability to carry on drying grain. Tie results of the experiments showed that under a definite wind-quantity ratio, we can save the energy consumption on the one hand, and avoid the germination damage of the rice grain on the other.The average energy consumption in the experiments is 840 k cal/kg water.It is 20%lower than the gemeral method of high-temperature rapid drying, but it takes longer time.

Abstract:本文对芒果引进中国的历史进行考辨。全文分四部分:1.考证现在栽培的芒果非中国原产,它应该是从印度或斯里兰卡传入的。2.驳芒果由唐代玄类从印度传入之说,考证玄奘在所著《大唐西域记》中提到的庵没罗果就是现在的沙果,而非芒果。3.驳清代吴其浚以为芒果在元代已经栽培之说,考证吴氏将黎檬误为芒果;又驳《珠江三角洲农业志》(1976)以为扁桃就是芒果之说,考证元代以前,广东没有芒果栽培。4.考证明代嘉靖十四年(1535)中国方志开始有芒果记载,其时并不普遍;它的传入,当在明代初年。芒果自明代传入以后,经过人工栽培,已有十多个品种。