米胚芽贮藏保鲜研究

 试验研究采用不同包装、包装真空度、温度和辐照对米胚芽贮藏期间延滞（酉合）败的作用。结果表明室温或低温贮藏中用二层袋真空包装，或单层袋加辐照贮藏对阻滞米旺芽（酉合）败均有一定效果。     

Water penetration into rice grains during soaking observed by gradient echo magnetic resonance imaging

The water penetration into a rice grain during soaking was monitored by three-dimensional gradient echo magnetic resonance imaging, which has the advantage of a short measurement time and a sufficient sensitivity for low-moisture samples. The water penetration route was compared between the milled and brown rice grains of two japonica cultivars. In normal milled rice grains of Koshihikari, water first penetrated the ventral side surface and the embryo attachment site of the endosperm, then migrated along the central line and transverse cracks, and finally diffused to all parts of the endosperm. In milled rice grains of Yamadanishiki with a white core, water quickly infiltrated into the cracks or chalky parts on the dorsiventral line and then diffused to the lateral side. In brown rice grains of both cultivars water penetrated extremely slowly and did not infiltrate directly into transverse cracks or the white core due to inhibition by the pericarp and seed coat. The central part of every grain allowed more water to penetrate. The route, pattern and speed of water penetration were determined by the morphological structure, crack formation and hardness distribution associated with the packing of the starch granules in the grain.     

Effects of twice harvesting on total dry matter yield of rice

We examined the effect of twice harvesting of forage rice with the first harvest at the full heading stage on total dry matter yield in the cultivars Taporuri, Mohretsu, and Hinohikari and in line Saikaishi 253 in southwestern Japan. Taporuri produced the highest total dry matter yield, with a value 60% higher than that of Hinohikari. The first crop of Taporuri had a longer duration of vegetative growth than those of Mohretsu and Hinohikari, and had the highest dry matter yield because of its greater weight per tiller than Hinohikari and its more tillers per square meter than Saikaishi 253, which had a similar duration of vegetative growth. The second crops of Mohretsu, Taporuri, and Saikaishi 253 had longer vegetative growth and higher dry matter yields than Hinohikari. Dry matter yields of both crops were closely related to the duration of vegetative growth and the weight per tiller, but not to tillers per square meter. These results suggest that cultivars with a long duration of vegetative growth, high weight per tiller, and adequate tillers per square meter can produce high dry matter yield in both crops. There was a significant interaction (P < 0.05) in total dry matter yield between cultivar or line and cultivation type. The total dry matter yield of Taporuri in twice harvesting was about 10% higher than that in once harvesting, whereas that of Hinohikari was about 10% lower. The suitability for twice harvesting ([total dry matter yield in twice harvesting]/[total dry matter yield in once harvesting]) was significantly positively correlated (r = 0.875) with the increase in dry weight before the full heading stage, but significantly negatively correlated (r = −0.903) with the increase in dry weight between full heading and the yellow ripe stage. Thus, cultivars with a high increase in dry weight before full heading appear to be more suitable for twice harvesting than those with a high increase between full heading and the yellow ripe stage. In addition, our study showed that twice harvesting can prevent lodging in Taporuri, thereby increasing the suitability of this cultivar as a forage rice. Our results suggest that twice harvesting can be performed in southwestern Japan and warmer regions.     

Effect of high-pressure treatment on rheological,thermal and structural changes in Basmati rice flour slurry

Rheological, thermal and structural changes in high pressure (HP) treated Basmati rice flour dispersions were studied as function of pressure level (350–650 MPa), slurry concentration (with 1:5, 1:3 and 1:2 flour-to-water ratios) and holding time (7.5–15 min). Rice flour dispersions exhibited a gradual liquid–solid gel transformation as they gelatinized and/or denatured and behaved as viscoelastic fluid following HP treatment. Mechanical strength (G′) of pressurized gel increased with applied pressure and rice concentration. Differential scanning calorimeter (DSC) thermograms of rice slurry measured after pressure treatment indicated a reduction in peak enthalpy in proportion with the extent of gelatinization and/or denaturation of starch and proteins. Pressure-treated rice samples had a progressively lower gelatinization temperature. A 15 min pressure treatment at 550 MPa was found sufficient to complete gelatinization of protein free isolated rice starch while the slurry required 650 MPa. The presence of proteins might have been responsible for the slower starch gelatinization in the rice slurry during pressure treatment. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier-transform infrared (FTIR) spectroscopy results indicated some minor changes in protein subunits and secondary structure of rice protein. This study has provided complementary information on pressure-induced changes in physical (thermal stability, overall structure) and molecular level (secondary structure) of rice protein.     

Effects of topography on the construction and efficiency of earthen weirs for rice irrigation in Northeast Thailand

Farmers in some parts of the Indochina Peninsula have been using earthen weirs to supply water to their rice fields, and the use of such weirs is especially prevalent in Northeast Thailand. Although now a typical rain-fed rice cultivation area, a significant percentage of rice fields in Northeast Thailand used earthen weirs before the extensive expansion of rain-fed rice fields that occurred in the early 20th century. In this study, we clarified some of the historical changes associated with the construction and use of earthen weirs and their effects on rice production. In particular, we investigated some of the topographic effects, such as terrain, catchment size, and slope grade, on water delivery. In addition, water delivery methods, construction periods, and the discontinued use of earthen weirs were examined with respect to regional influences and topography. Earthen weirs were found to be most suitable in areas that exhibited complementarity between the riverbed slope and the water catchment. The type of earthen weir was dependent on the magnitude of the riverbed slope. Earthen weirs have been constructed continuously on steeper upstream slopes of rivers for more than a century, while weir construction on lower riverbeds with larger catchments appears to be more recent.

强化栽培条件下水稻的根系特征及其与产量形成的关系

以协优527为材料，研究了强化栽培条件下水稻的根系特征及其与产量形成的关系。结果表明，与常规栽培相比，强化栽培能明显增加从分蘖至成熟各生育时期的单株根系干重，降低齐穗后根系中可溶性糖含量，提高生育后期根系的生理活性及磷含量，特别是在籽粒灌浆结实的关键时期，SRI栽培的根系伤流强度明显高于接常规栽培。因此，强化栽培可以延缓后期根系及叶片衰老，提高结实率及千粒重，进而提高产量。     

丘陵区水稻品种多样性混合间栽控制稻瘟病研究

在对 2个主栽品种 (生产上推广的当家杂交稻组合 )和 2个间栽品种 (优质感瘟 )进行 RGA遗传背景研究的基础上 ,配成 4个混合间栽组合。经在祁东 (丘陵 )小区试验和示范比较 ,结果都表明品种混合间栽后 ,间栽品种叶瘟的防治效果达 48.86 %～ 79.91% ,穗瘟的防治效果达 12 .38%～ 6 3.5 7% ;混合间栽的主栽品种与净栽主栽品种比较 ,叶瘟和穗瘟的病情严重度差异不大。在产量上 ,混合间栽比净栽均表现出不同程度的增产 ,幅度在 1.5 7%～ 12 .71%。基于本研究结果 ,选择抗瘟性遗传背景差异大 ,株高差异突出的品种以 1行优质稻间 5行主栽品种混合栽培 ,能起到控瘟增产的作用。     

Assessment of pearl millet vs rice based diets for bioavailability of four trace metals

Cereals including millets are consumed in India as a staple with wide variety of pulses and vegetables in varying proportions. Trace mineral contents of pearl millet are two to ten times higher than that of rice. Comparative performance of pearl millet based (PM) diets as against rice based (RB) diets in terms of trace mineral bioavailability was studied, based on the prevailing dietary patterns in India. In vitro percent dialysability of zinc, iron, copper and manganese under simulated gastrointestinal conditions was considered as indicator of metal bioavailability. Dialysable zinc and iron were estimated using 65 Zn and 59 Fe as tracers, while dialysable copper and manganese were measured by Atomic absorption spectrophotometer for 20 food items and 15 RB and 17 PM diets prepared from these items. Results indicated that percent dialysability of zinc and copper was higher for RB diets than PM diets, while that of iron and manganese were comparable. Total dialysable iron, copper and manganese in PM diet was 2 to 4 times higher than RB diet.     

春油菜高光效结角层结构的研究

通过对内蒙古海拉尔地区春油菜结角层的研究,分析了结角层中角果组成,分布及其性状的变化,结果表明:1、春油菜结角层较薄,PAI较小,提高产量主要是控制下位分枝的生长,改善结角层内部的光照条件,形成一个高光效的结角层结构。群体直立不倒,各枝序排列有序。2、提高结角层生产力的关键是在结角层的纵向上提高千粒重、横向上增加角粒数。3、各枝序的生产力与它们的结角起止高度密切相关。     

Comparison of sulfurous acid generator and alternate amendments to improve the quality of saline-sodic water for sustainable rice yields

The prolonged irrigation with marginal quality water can cause secondary salinization of soils, which necessitates for better understanding of water management alternatives. Relative performance of sulfuric acid and gypsum is still controversial to counter sodium hazards in soil/water system. As an alternative, sulfurous acid generators (SAG) are also being marketed. But up-till-now, there is not even a single field study published in scientific journals about their efficiency and economical viability for the treatment of saline-sodic water. Therefore, a field study was carried out to compare the effectiveness of SAG and alternate amendments applied on an equivalent basis to grow rice crop. SAG treatment of saline-sodic tube well water decreased only residual sodium carbonate (RSC) from 5.4 to 3.6 mmol_c l⁻¹, and had no beneficial effect on its sodium adsorption ratio (SAR) or electrical conductivity (EC). All the treatments kept soil EC and SAR around their respective threshold levels. For paddy yield, SAG, sulfuric acid, and gypsum treatments depicted nonsignificant differences. SAG and sulfuric acid treatments of water were about six times expensive than that of gypsum. It was concluded that soil-applied gypsum, to counter sodic hazards of irrigation water, is economical to sustain irrigated rice in dry regions.