With japonica rice Wuyunjing 7 and indica rice Fengyouxiangzhan as test materials,effects of row-spacing on morphological and eco-physiological characteristics of rice were studied.The yield of medium row-spacing treatment(30 cm×13.3 cm) was the highest,while that of narrow row-spacing(20 cm×20 cm) was the lowest,with a significant difference at 0.05 level.Medium row-spacing treatment significantly diminished internode length and enhanced internode thickness,wall thickness,the number of vascular bundles of internode,and the lodging resistance compared to wide row-spacing(40 cm×10 cm) and narrow row-spacing treatments.The content of dry matter in basal internode at the heading stage and the 20th day after heading,and the amount of dry matter transferred to grain at the filling stage were the highest at the medium row-spacing treatment.Moreover,there were appropriate leaf area index and higher photosynthetic rate of flag leaf at medium row-spacing treatment.Furthermore,the distinctive differences were found in the content of CO2,light intensity,air temperature and humidity in the population among different row-spacing treatments,and medium row-spacing treatment showed ideal microclimate within the population of rice.It clearly suggested that medium row-spacing treatment is necessary for high-yielding cultivation of rice.

Four rice cultivars with different amylose content were used to investigate the starch structure and RVA pasting properties in this study. The results showed that differences existed between rice cultivars. Relative crystallinity decreased and setback viscosity increased with increasing amylose content, and there were significant negative and positive correlations between relative crystallinity and amylose content, amylose content and setback viscosity, respectively(r=-0.964, r=0.997). Correspondingly, the significant negative correlation of setback viscosity with relative crystallinity was discovered (r=-0.960). The crystallinity patterns of four rice starch cultivars showed as typical A type with amylose content ranged from 3.43% to 21.65%. Endosperm structure was different between glutinous or low-amylose and non-glutinous or high-amylose rice, and the arrangement and shape were different between the dorsum and abdomen of amyloplast in rice endosperm. The results implied that the shapes and arrangements of starch granule in endosperm might influence the relative crystallinity of rice starch.

【Objective】 In order to reveal the relations of leaf color and nitrogen uptake of rice.【Method】 The dynamic change of upper-most three leaves color and nitrogen uptake rate of rice was studied in solution experiments.【Result】 There were significant changes of leaves colors and nitrogen uptake during growing period.The three peaks emerged at the days after transplanting,20 days before heading,and heading and anthesis,low vallies emerged at jointing stage and 10 days before heading.The rate of nitrogen uptake correlated closely with SPAD values of rice leaf after two weeks.【Conclusion】 The dynamic change of leaf color of rice is mainly caused by nitrogen uptake of root,the changes of leaf color and nitrogen uptake rate are limited by inherent rhythm of its oneself,especially with constant nitrogen concentrations of solution.

以武香粳9号和武运粳7号为材料,研究了旱育苗床持续饱和水分对水稻秧苗体内物质代谢的影响.结果表明,与旱育秧苗相比,维持旱育苗床饱和水分9～12 h,可使植株硝态氮、叶片硝酸还原酶活性、地上部可溶性糖含量、根系可溶性蛋白、根系活力等物质生理特性达到最优状态;随着苗床持续饱和水分时间的延长,叶片和根系中IAA和iPAs含量一直持续增加,而叶片IAA/iPAs比值逐渐降低,根系IAA/iPAs比值逐渐增加.

The eco-farming model of rice-duck mutualism is a comprehensive production technology combining the planting-breeding complex with eco-environment protection.Raising ducks in paddy fields has demonstrated positive effects on paddy ecology,such as intertilling and weeding,controlling insects and diseases,saving cost and improving soil fertility,stimulating rice growth,which significantly improves the system′s economic,social and ecological benefits.The status of the experiment and application of the technology of rice-duck mutualistic eco-farming system in China has been summarized,and some issues that need to be perfected and explored in future are put forward.pollution-free agriculture

A three-year experiment was conducted in order to examine the effects of potassium (K) application rates on plant K accumulation, K use efficiency and grain quality of japonica rice (Wuxiangjing14 and Wuyujing3) from 2000 to 2002 in Dongtai, Jiangsu, China. When K fertilizer was applied as basal dressing, K uptake of rice population amounted to maximum at the K2O application rate of 12.8 kg/667m2 and excessive-fertilization decreased population K uptake, grains K absorption always increased with the increase of K fertilizer application rate, only the increment extent decreased gradually. Potassium uptake by rice population peaked in the growth season from the elongation stage to the heading stage. Non-fertilization and excessive-fertilization enhanced the proportion of plant K uptake before the elongation stage, but reduced effective panicles. With one-time application of K fertilizer as basal dressing, the highest grain yield and quality occurred at the level of 1∶0.8 of N∶K2O ratio, which significantly increased the percentage of earbearing tiller and setting percentage and K physiological and agronomy efficiencies. Also, low chalkiness degree and amylose content were found at this level. Compared to one-time application of K fertilizer as basal dressing, fertilization as panicle fertilizer caused increases in plant K uptake and proportion from elongation stage to heading stage, the number of filled grain, the setting percentage and gel consistency. Moreover, K fertilization as panicle fertilizer significantly decreased chalkiness degree and amylose content, resulting in considerable high grain yield and quality.

The production of nuisanceless rice was conducted by the technique of rice-duck mutualism without applying any pesticide and chemical fertilizer. The results showed that compared to the control, the effect of eliminating weeds was over 99.4%, and the cardinal numbers of plant diseases and insect pests reduced obviously. Nutrients and dissolved oxygen in paddy water and rapidly available nutrients in soil increased, but after maturing stage, compared to basal fertility, rapidly available P and K decreased. The N, P, and K absorption amounts of rice plant, rice yield, setting panicles rate, filled grains and ripened rate increased. The milling, appearance, nutritional, cooking and eating quality of rice improved, especially in reducing chalkiness. The comprehensive benefits of paddy field enhanced obviously.

以粳稻品种武香粳9号和籼稻品种H97-322为材料,在基础地力和穗肥施氮相同的条件下,研究了氮素基、蘖肥不同施用水平对水稻氮素吸收利用的影响.结果表明:(1)各处理水稻相对吸氮速率随生育进程而降低,其降低速度随氮素基、蘖肥占总施氮量比重增大而加快.增施氮素基、蘖肥,增加了拔节前吸氮量,但抑制了拔节后吸氮,尤其是显著增加了有效分蘖临界叶龄期至拔节期阶段吸氮量,显著降低了抽穗期至成熟期阶段吸氮量;增施氮素基、蘖肥,虽然有利于拔节前氮素基、蘖肥利用率的提高,但不利于整个生育期的氮素基、蘖肥利用率和总氮肥利用率的提高.(2)氮素基、蘖肥用量适宜,相对吸氮速率平稳减小,各生育阶段吸氮比例协调,氮素利用率和产谷效率协同提高是高产的重要条件.研究还表明目前一般的氮素基、蘖肥用量存在偏高现象.

Effect of nitrogen application rate(NAR,0,10,20 and 40 g·m -2 )on morphological traits and physiological characters of rice dry seedbed seedlings at transplanting stage was studied by using the japonica varieties of Wuxiangjing 9 and Wuyunjing 7.The results showed as follows.When NAR was 20 g·m -2 ,dry seedbed seedlings had the largest leaf area,the highest dry matter,the most white roots and tillers per plant,the highest content of plant nitrogen,leaf NO - 3 N and plant soluble sugar,the strongest root vigor of roots reducing activity,oxidation activity,active absorption area and new roots emergence vigor,the biggest protection enzyme activity of superoxide dismutase(SOD),catalase(CAT)and ascorbic acid peroxidase(AsA POD).The root length and the dry weight ratio of root to shoot of dry seedbed seedlings reduced gradually and the leaf chlorophyll content increased continuously with an increase in nitrogen application rate,but the increment extent decreased gradually.Little or excessive nitrogen fertilizer application decreased roots vigor and protection enzyme activity and reduced growth and physiology superiorities of dry seedbed seedlings.

给出了用于度量水稻群体植伤的一组指标:植伤持续期、植伤强度和相对植伤势.分析了栽插密度、施用 N素对盐粳 187群体植伤的影响,结果表明,栽插密度对盐粳 187群体植伤影响不显著,而施用 N素则对群体植伤有显著影响.

以武香粳9号为材料研究了不同穗肥施氮时期对水稻籽粒蛋白质积累的影响.结果表明:穗肥的施用提高了籽粒发育过程中单位干重蛋白质含量,以在倒0.5叶施用氮素穗肥影响最大;随施肥时期的延迟,稻米粗蛋白和谷蛋白含量逐步上升,醇溶蛋白含量逐渐降低;倒2.5叶施氮减少了强、弱势粒中蛋白组分的分布和含量,倒0.5叶施氮与此相反;胚乳蛋白组分在花后15 d到25 d甚至更晚的时间合成完全.

采用盆栽干旱胁迫方法对苎麻品种圆叶青不同生育期抗旱性差异进行了研究,结果表明:在干旱胁迫下,苎麻品种圆叶青农艺性状、干物质积累和产量的胁迫指数均以苗期>工艺成熟期>旺长期,旺长期是苎麻品种圆叶青干旱胁迫敏感期.

Greenness and nitrogen content of each leaf on main stem of different japonica and indica rice varieties under different nitrogen levels were investigated. Results showed that the fourth leaf from the top exhibited active changes with the change of plant nitrogen status. When the plant nitrogen content was low, its color and nitrogen content were obviously lower than those of the three top leaves. With the increase of plant nitrogen content, the color and nitrogen content of the fourth leaf increased quickly, and the differences of color and nitrogen content between the fourth leaf and the three top leaves decreased. So, the fourth leaf was an ideal indication of plant nutrition status. In addition, color difference between the fourth and the third leaf from the top was highly related to the plant nitrogen content regardless of the variety and development stage. Therefore, color difference between the fourth and the third leaf could be widely used for diagnosis of plant nutrition. Results also indicated that the minimized color difference between the fourth and the third leaf at the critical effective tillering, the emergence of the second leaf from the top, and the heading was the symbol of high yield. Plant nitrogen content of 27 g kg^(-1) DW for japonica rice and 25 g kg^(-1) DW for indica were the critical nitrogen concentrations.

A comparative study on the photosynthesis and senescence in two line and three line hybrid rice indicated that leaf senescence was associated with the decrease in superoxide dismutase activity and chlorophyll, soluble protein content, and the marked increase in malondialdehyde content. Significant differences were observed within the same kind of hybrid rice but not between the two kinds of hybrids, so did for the canopy photosynthetic rate of these hybrids. After heading stage, the canopy photosynthetic rate correlated positively with the dry matter production during ripening stage.

Relationships between nitrogen contents in leaf at different stages and tiller emergency,spike,grain and yield formation were studied with six middle and late maturity rice varieties.The results indicated that tillering percentage increased with enhancing nitrogen content in leaf,suitable nitrogen contents in leaf for tillering emergency and termination enhanced with the delay of tillering stage.Spikelet number per spike was mainly affected by the nitrogen contents in the first and second leaf from the top,productive grain percentage was related to nitrogen content at heading stage,and suitable nitrogen contents in leaf for spikelet differentiation and productive grain formation were 27?28 g·kg -1 and 25 g·kg -1 in Japonica and Indica rices respectively.Color of four top leaves in main stem at N-n,N- 1 and heading stage was similar with or slightly darker than that of three top leaves,which was a common characteristic for high yield in different rice varieties.In addition,suitable leaf nitrogen content indices for high yield in rice plant were provided.

By different nitrogen treatments and manual regulation ofsource-sink ratio, dynamic states of bleeding at neck-panicle node and basal internode of rice were studied. There were very difference in dynamic changes and amino acids of bleeding. The effects of source-sink ratio regulations on them were also significant. It indicate that the bleeding at neck-panicle node has relationship not only with root source activity, but also with leaf source, sheath-stem source and sink activity. The optimum ratio N fertilizer applied in early and late growth stage could improve bleeding intensity of rice.

Rice dry nursery seedlings (DNS) firstly strengthened the growth of root system, R/T of DNS was higher than that of moist nursery seedlings (MNS) before 3. 5-leaf stage. Dry matter weight (g) per cm plant height of DNS was higher than that of MNS after 3. 5-leaf stage. DNS had characteristics of stocky seedlings. The contents of soluble sugar, starch, total N, protein-N and non-protein N in DNS were higher than that in MNS. NRA of DNS was 4. 12-5. 18 times higher than that of MNS; content of NOR-N in the stem . sheath of DNS was 30. 1 times higher than that of MNS. The activity of ATPase in DNS was 4. 61%~94.34% higher than that in MNS. The activities of SOD and CAT in DNS were 6.25% ~31. 82% and 132. 00%-150% higher than that in MNS respectively. Content of MDA in DNS was 16. 98%~23. 97% higher than that in MNS. Content of proline in DNS was 2. 29-4. 08 times higher than that in MNS. DNS was more sensitive to wilt than MNS at water stress. But the loss of water rate of isolated leaves of DNS decreased in temporary wilting time, and was 33. 2600 lower than that of MNS. So DNS had physiological mechanisms of drought resistance while DNS was adapted to the environment of dry nursery. The physiological characteristic of drought resistance of DNS was the physiological base of growth superiority of DNS after transplanting.

试验表明,播期影响水稻齐穗期和产量,产量取决于颖花量和籽粒充实度,在相同密度下,播期对籽粒充实度的影响显著大于对颖花量的影响.齐穗后有效积温与群体籽粒充实度间多呈显著或极显著的正相关,而齐穗后的光照累计值对群体籽粒充实度却有趋向显著的负相关.究其原因,是灌浆期出现温光错位(MTI)造成的,发生MTI的条件是:候均日温降至15.5 ℃以下,温度降差3 ℃以上,时滞1d的候均日照升差达4h以上.进一步分析表明,籽粒充实度(GFG)与抽穗后有效积温(＞10 ℃,ETS)间有下列关系:GFG=(a+b ETS)ETS.据此,可以确立水稻品种的最迟安全齐穗期,进而指导对水稻品种的合理利用.

为提高干旱、半干旱缺水地区水稻栽培效益,1998～1999年在江苏省东海县进行了覆膜旱管水稻栽培试验与示范.覆膜旱管条件下水稻单株分蘖数、叶而积指数和地上部干重等都显著大于不覆膜旱管水稻,产量构成因素更趋协调,从而缓解了水份对植株的胁迫程度.与露地栽培旱作物(如陆稻、玉米)相比,单位面积产量提高14.3%～39.8%,产值增加24.5%～42.9%,可以示范推广.

以武运粳七号为材料,对水稻旱育秧苗和湿润秧苗根系生长的生理物质活性进行了比较研究.结果表明,旱育秧苗总根数、白根数、根系活力及活跃吸收面积较高,根系C/N稍低于湿润秧苗,可溶性糖和硝态氮含量是湿润秧苗的数倍至数十倍, 糖和硝态氮的较高积累不仅有利于维持秧苗根系正常的生理活动,也为移栽后秧苗根系生长和新根的发生贮备了充足的营养物质.旱育秧苗移栽前根系中脱落酸(ABA)、吲哚乙酸(IAA) 含量高于湿润秧苗,异戊烯基腺嘌呤(iPAs)、赤霉素(GA3)含量低于湿润秧苗,而移栽后3 d,IAA、GA3、iPAs含量均高于湿润秧苗.