| Salinity and alkalinity is one of the important harm factors in rice region. Hei Longjiang province that is the main cultivation areas in cold region for northern japonica rice is important commodity grain production base for China. As well as the salinity and alkalinity culticated area is567000hectares which accounts for about5.96%of total arable land in Hei Longjiang Province. So it was important for commissariat security in China to study the physiological of saline-alkali tolerance for rice and growing the rice rationally in utilization of saline-alkali land. In order to definitze the effect on the salinity and alkalinity of growth, grain filling, yield and quality of rice, three kinds of rice Ji Yujing, Sui Jing5and Song Jing6were used as material, three treatments soil which were named low saline-alkali soil S1, medium saline-alkali soil S2and high saline-alkali soil S3were set, controlling with soil SO from Northeast Agricultural University Xiang Fang practice basd. The starch and compontent accumulation and key enzyme in composing starch in salinity and alkalinity stress were observed which filled the blank and provided a theoretical basis for the high yield and quality of japonica rice in cold region. The results for the research can be summarized as follows:1. The growth period of rice delayed with saline-alkali increasing. No significant effect was observed that regreening stage on saline-alkali while it had significant effect on tillering and heading stage. Under S3, tillering stage of Ji Yujing, Sui Jing5and Song Jing6were delayed12d,13d and16d respectively compared to control, and heading stage were putting off10d,14d and13d. It was obviously short for grain filling time which were decreasing1～4d,2～7d and2～6d for Ji Yujing, Sui Jing5and Song Jing6in saline-alkali stress.2. Saline-alkali decreased the height of rice obviously that the height was shorted with saline-alkali increasing. There was no significant different of height between SI and S2while obviously different with SO, S3. No significant differences were obviously observed that the effect on saline-alkali of height for different kinds of rice.3. The tiller of rice that showed a single-peak curve was reduced with saline-alkali incrasing in saline-alkali stress. The tiller of Ji Yujing, Sui Jing5and Song Jing6decreased43.2%,24.9%and44.7%comparing with control treatment in S3. Saline-alkali was significantly delayed the tillering time and peak time of rice, and the soil salini-alkali was higher, the delay time was longer. The tillering time of three kinds of rice were delayed5～10d, and peak time delayed10-20d under S3. Differences of effect on saline-alkali of tillering of rice between different kinds was observed, Sui Jing5showed strong resistance to saline-alkali whose tiller number decreasing amplitude less than Ji Yujing and Song Jing6.4. Grain weight of rice increasing process showed "S" curve change in saline-alkani stress. It was the critical period for weight increasing of rice that the weight raised rapidly duing10-35d after full heading. Saline-alkani stress delayed grain filling time and reduced filling rate, especially duing10～35d after full heading, the max filling rates of Ji Yujing, Sui Jing5and Song Jing6were delayed10d,5d and10d, decreasing to30.2%,33.1%and42.4%comparing with control treatment. The effect of saline-alkali stress on grain filling was large, but different varieties showed differences, the order of effect was Song Jing6>Ji Yujing>Sui Jing5.5. It was obviously observed that saline-alkali stress inhibited ADPG and soluble starch synthase enzyme activities. Before the peak of enzyme activity, enzyme activity values of saline-alkali stress were lower than that of the control, at the same time time of peak was delayed and the peak was declined. The correlation analysis showed that ADPG and soluble starch synthase activity were associatied with yield significantly of three rice varieties during5-15d and30-45d after full heading. The differences of the effect on saline-alkali stress of key enzyme composing starch between three kinds of rice were exited. The declining amplitudes of saline-alkali tolerance varieties Ji Yujing and Sui Jing5were small, while Song Jing6was large.6. Saline-alkali stress inhibited the rice grain starch accumulation obviously. The inhibitory effect was stronger with the soil saline-alkali being higer, especially during10-25d after full heading. The effect on rice grain accumulation was different of different saline-alkali, compared with control, the decreasing amplitude in S1was small, while in S2and S3were large. There excited different effects on grain different components of dropping amplitude of amylose content was small, while amylopectin and total starch content were large. There was different effect on grain starch components of saline-alkali stress, the effect of Song Jing6was large, and saline-alkali tolerance varieties Ji Yujing and Sui Jing5were small.7. Rice spike length, spike weight, two branch number per hole, spike, spike rate and grain weight were reduced significantly with saline-alkani stress, while the effects of one branch number, grain density, seed setting rate and grain number per spike were small. Yield of rice was dropped with saline-alkani increasing, differences excting in species, no significant differences were observed between Ji Yujing, Sui Jing5and control in S1, while S2and S3decreased significantly the yield, and saline-alkali stress reduced the yield of Song Jing6significantly.8. Saline-alkali stress declined the quality of rice. The influence of milling quality of rice showed that the order of effect of saline-alkali stress was head rice rate, milled rice rate, brown rice rate. Chalky rice percentage was raised in saline-alkali stress, chalky rice percentage was bigger with higher saline-alkali, and appearance qualities decling. As well as saline-alkali stress reduced the grain gel consistency and amylase content, reduing in rice taste variation and evaluation grades down. |
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