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10 July 1997, Volume 11 Issue 3 Previous Issue    Next Issue
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研究报告
研究简讯
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研究报告

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Studies on Polymorphism of Rice Prolamines Ling Jianqun,He Zuhua,Ma Zhichao,Li Debao 1997, 11(3): 129-135 .  Abstract ( )   PDF (462KB) ( )   Rice prolamines of 40 lines were studied with SDS-PAGE, and relative quantities of 16kDa, 13a, 13b and 10kDa composition were analysed by TLC scanning. The results showed that there were obvious polymorphism of prolamine composition among the lines studied; Difference of genotypes of the lines not only resulted in the absence of one or two prolamines composition, but also influence the percentages of the four composition, and the total prolamine quantities. It also appeared that 13kDa and 10kDa prolamines had some relationship in their contents as in the case of 13a and 13b; Compared with 13kDa and 10kDa prolamines, 16kDa was relatively stable in its content.These evidences suggest that the regulation mechanism of the rice prolamines accumulation would be very complicated during the seed developing.

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To Improve the Integrated Photosynthetic Capacity by Means of Making Hybrid Rice (in English) Tu Zengping,Lin Xiuzhen,Cai Weijuan,Yao Pingfei,Li Xiaolin,Clanton C. Black,Paul A. Counce 1997, 11(3): 136-140 .  Abstract ( )   PDF (235KB) ( )   The hybrid rice Le/Qi from crossing US rice Lemont with South China rice Qiguizao possesses improved integrated photosynthetic capacity both in light interception and light conversion efficiency, comparing with its parents, Therefore, give remarkably higher solar energy use efficiency of 53%～62% and 8%-15% than Lemont and Qiguizao, respectively, both in Arkansas of USA and in Guangzhou of China. Extended experiments with 12 hybrid combinations from US rice and South China rice demonstrated that nearly all the hybrids possessed remakably improved integrated photosynthetic capacity, quicker development of leaf area, as indicated by higher biomass production over US parents, and stronger capacity to scavenge toxic free radicals, therefore, giving higher efficiency of photosynthetic energy conversion under high light intensity over South China parents.

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The Process of Embryo Sac Formation and its Stages Dividing in Rice Liu Xiangdong,Xu Xuebin,Lu Yonggen,S H Zee 1997, 11(3): 141-150 .  Abstract ( )   PDF (855KB) ( )   The process of embryo sac formation and development in rice (cultivar IR36) was studied by the modified GMA semi-thin serial sectioning technique. Clear photos of various embryo sac formation stages were tamed. The results showed: a) The cells of dyad and tetrad from megasporocyte meiosis Ⅰ and meiosis Ⅱ were all unequal in size. b) Fixed patterns of orientation of the three mitotic events in the mono-nucleate embryo sac. c) Obvious changes in the process of polar-nuclei development were observed. d) Regular changes in the appearance and disappearance of starch grains existed in each stage of embryo sac formation. According to the characteristics of embryo sac formation, the process of rice embryo sac formation could tentatively be divided into 8 stages, i. e, archesporial cell formation stage, megasporocyte formation stage, megasporocyte meiosis stage, functional megaspore formation stage, mono-nucleate embryo sac formation stage, embryo sac mitosis stage, eight-nucleate embryo sac developing-stage, and embryo sac matured-stage. The relationships between the stages of embryo sac development and the morphological changes of spikelet were also described.

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Inheritance of Heading Time in Two Middle Indica Cultivars of Rice Gu Xingyou,Gu Minghong 1997, 11(3): 151-154 .  Abstract ( )   PDF (269KB) ( )   Nanjing 11 and Wujinxiangxian are two middle indica cultivars from Jiangsu, China and the vegetative growing period of their F1 was too long to mature normaly in the locality. To investigate the genetic machanism of the transgression the heading time of the F1, F2, BC1, BC2 and F3 plant-lines from six F2 late mature plants were observed under natural or short day conditions. The observations showed that there existed the differentiations between the parents in three major gene loci controlling photoperiod, which conferred the F1 and their F2 late plants on intensive photosensitivity in the model of gene complementation , and that the two of the complementary genes were from Naming 11 and the other one from Wujinxiangxian. It was deduced that above genes in the cultivars originated from cultivars of South or Central China and Southeast Asia, respectively, based on the analysis of their pedigrees.

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Rice (Oryza sativa L. indica) transformation by Agrobacterium tumefacien Xiao Han,Huang Danian 1997, 11(3): 154-154 .  Abstract ( )   PDF (54KB) ( )

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Studies on Grain Qualities and Agronomic Characters of Early Season Indica Rice Cultivars Tested in Regional Trials During Guo Yinyan,Zhang Yunkang,Ye Mingju,Hu Bingmin,Chen Kunrong 1997, 11(3): 155-159 .  Abstract ( )   PDF (228KB) ( )   The trends of improvment of grain qualities and agronomic characters of the early season indica rice cultivars tested in the regional trial of Zhejiang Province during the "Eighth Five-Year Plan" period were analyzed. In comparison with the cultivars tested in the "Seventh Five-Year Plan" period, the grain qualities of the cultivars in "Eighth Five-Year Plan" period were much more improved accompanied by a tendency of growth period shortening. panicle number decreasing and panicle enlarging, especially in late maturing rice cultivars. In terms of various quality characters, most of the cultivars tested were, however, not satisfactory in head milled rice recovery, chalkness ratio, chalkness area and grain shape. Analysis of various variance components of the qualities to be ameliorated showed that head milled rice recovery was affected by cultivar × year interaction an a larger extent than by cultivars effect, while other qualities were mainly affected by cultivar effect.

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Relation Between Axillary Bud Growth and Matter Accumulation of Stem-Sheath After Heading of Main Crop in Hybrid Rice Xu Fuxian,Xiong Hong,Hong Song 1997, 11(3): 160-164 .  Abstract ( )   PDF (337KB) ( )   The relation between axillary bud growth and matter accumulation of stem-sheath after full heading o f main crop were studied with hybrid rice combinations Shanyou 63, K-you 3 and K-you 5 in 1993-1995. During 15 days after full heading of main crop, most of photosynthates were transported to panicles, their axillary buds were stretched slowly under well light and N applied condition. At 20 days after full heading, or the grain filling at about 90% level, more photosynthates of the main crop were transported to their stems, the axillary buds were stretched quickly and effect of improving light condition as well as N application for accelerating axillary buds growth were appeared. Highly significant negative correlations were observed between the grain filling rate of main crop and stretching rate of their axillary buds, between amount of dry matter accumulation of panicles with harvest index of main crop and length of the axillary buds.

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Effects of N, K Supply at Initial Stage of Panicle Emerging on Physiological Traits in Flag Leaf of Hybrid Rice Shanyou 63 Wang Yongrui,Zhou Jie 1997, 11(3): 165-169 .  Abstract ( )   PDF (336KB) ( )   In pot experiment, the physiological traits in flag leaf of hybrid rice Shanyou 63 were studied under nitrogen, potassium, and nitrogen plus potassium supply at initial stage of panicle emerging. The nitrogen plus potassium supply at initial stage of panicle emerging, increased the chlorophyll content, photosynthetic rate and activities of sucrose phosphate synthetase (SPS), peroxidase (POX) , superoxide dismutase (SOD) and nitrate reductase (NR),but decreased the respiration in flag leaf at heading, milky and dough stage of hybrid rice Shanyou 63, enhanced the soluble sugar content and soluble protein content of the leaf as well as improved activity of the root system. The 14C-metabolites translocated more from flag leaf, distributed more in panicle and IAP [14C export from flag leaf(%)×14C in panicle(%)×100] when N plus K supplied to the soil in pots at initial heading stage than those of other treatments. It may be an innovative agricultural technology to increase the filled grain percent, 1000-grain weight and grain yield by N plus K supply at initial panicle emerging stage.

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Effect of Air Temperature,Water and Fertilizer Management on Methane Emission from Middle-Season Rice Fields Lu Wanfang,Chen Wei,Guo Wanmo,Duan Binwu 1997, 11(3): 170-174 .  Abstract ( )   PDF (198KB) ( )   During 130 days of middle-season rice growing period, the methane emission was diel determined by the computer automatic controlled analysis system on rice fields with the four patterns of water and fertilizer management. Under the inorganic fertilizer + green manure, continuously irrigation, the methane flux was 464. 0 mg/m2·d, that was the most amount compared with other treatments. The lowest methane flux was 180. 5 mg/m2·d in inorganic fertilizer + green manure, intermittent irrigation. Under the inorganic fertilizer + green manure, commonly irrigation and inorganic fertilizer, commonly irrigation , the methane fluxes were 260.1 and 198. 9mg/m2·d respectively. During 65 days after transplanting, except treatment of continuously irrigation, the methane emission amount was about 77%-93% to total emission of the rice growing season. Amount of methane emission was closely related to the air temperature. Draining rice field could reduce the methane emission.

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Study on Method of Measuring Pollen Fertility of F1 Between Indica and Japonic and Gamete Fertility Li Zichao,Lu Dihui,Zhao Shixu,Wang Xiangkun 1997, 11(3): 175-178 .  Abstract ( )   PDF (354KB) ( )   Five F1s between indica and japonica rice, one DH line 96-5 with low panicle fertility and one variety CPSLO17 (Control) were used. Their panicle fertility was tested, and their pollen fertility was also done by two methods, I2-KI-stain and haematoxylin-stain. The latter was a new way by which the two normal sperms were observed in mature fertility pollen of F1 between indica and japonica rice. The results showed that the pollen fertility by I2-KI-stain and panicle fertility was significantly different. However, the pollen fertility by haematoxylin-stain and panicle fertility showed no difference. Therefore, the partly sterile appeared not only in male gamete but also in female gamete and they possibly were both equal.

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Genotypic Differences in Potassium Contents of Rice Seeds Liu Guodong,Liu Gengling 1997, 11(3): 179-182 .  Abstract ( )   PDF (156KB) ( )   Seed potassium contents in 6 wild rice, 53 japonica rice, 153 indica rice and 28 indica hybrid rice from 25 countries and areas were determined in flame photometry. The average seed potassium contents of the four kinds of rice were arranged in such order: indica hybrid combinations, japonica＞indica＞wild rice. The both extremes of　the seed potassium contents in japonica, indica, wild rice and indica hybrid genotypes were 0. 4774 % and 0.2 175%,0.4495 % and 0.2165 % , 0. 2508 % and 0. 1381 %, and 0. 3763 % and 0. 3018 %, respectively. The genotypic differences were high significant. The frequency distribution of the seed K contents in the 234 cultivated genotypes resembled normal distribution.

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Effect of Temperature on Rice Chalkiness Formation and Changes of Materials in Endosperm Shen Bo,Chen Neng,Li Taigui,Luo Yukun 1997, 11(3): 183-186 .  Abstract ( )   PDF (193KB) ( )   Under two treatments of temperature i. e. high temperature (day/night: 33℃ /29℃ ) and proper temperature (day/night: 26℃ /22℃ ) in growth chamber, grain weight, water content, starch, soluble sugar and protein content and Q enzymes, starch phosphorylase, proteinase, peroxidase in endosperm during grain filling were continuously measured in early indica rice Luhongzao 1 (more chalkiness ) and Zhongyouzao 3 (less chalkiness ).With high temperature treatment, peaks of materials synthesis (or transformation) and enzyme activity in endosperm were earlier than those of proper temperature treatment. It affected the sequence and pattern of changes of materials and enzymes in endosperm during normal grain filling, and resulted in rice chalkiness increasing.

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Studies on Earliness of Indica-Japonica Hybrid Rice Cao Liyong,Shen Zongtan 1997, 11(3): 187-189 .  Abstract ( )   PDF (180KB) ( )   The growth period duration of indica-japonica hybrid rice is often very long, which made it difficult to select fine suitable crosses for double seasonal hybrid rice. Using male sterile line Zaoxian A with a dominant earnness gene as a parent could reduce growth period duration for about 17 days, while grain yield might not decrease significantly.

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Relationship Between Rice Leaf Senescence and Membrane Lipid Peroxidation During Grain Growth Duan Jun,Liang Chengye,Zhang Mingyong,Huang Yuwen,Liu Hongxian 1997, 11(3): 190-192 .  Abstract ( )   PDF (184KB) ( )   After 1/3 of spike and whole spike being removed at flowering stage, some physiological and biochemical indices of rice leaf senescence and membrane lipid peroxidation were determined. The results indicated that: Removing both 1/3 of spike and whole spike significantly delayed rice leaf senescence as indicated by higher chlorophyll and protein levels just after manipulative treatments, however, the membrane lipid peroxidation level decreased as indicated by lower malondialdehyde (MDA) content only after 7 days from manipulative treatments,the activity of superoxide dismutase (SOD) changed very little after treatments. The above results indicated that the membrane lipid peroxidation was not the primary cause of leaf senescence in rice at the grain development stage.