Limited information is available concerning the mineralogy of paddy soils in the southeastern China.Using chemical methods in conjunction with X-ray diffractometry, we studied the mineral composition of three paddy so...Limited information is available concerning the mineralogy of paddy soils in the southeastern China.Using chemical methods in conjunction with X-ray diffractometry, we studied the mineral composition of three paddy soils: Jinghua (paddy soil on Quaternary red clay), Fuyang (Hapl-percogenic loamy paddy soil), and Shaoxing (gleyic clayey paddy soil). All the soils contained quartz, mica, vermiculite, chlorite and kaolinite, and the distribution of these minerals varied with soil particle size fractions. The clay fraction of the F’uyang and Shaoxing soils also contained smectite. Although X-ray data did not show the presence of smectite in the Jinghua soil, this mineral was identified by the chemical method, suggesting a transitional property of the mineral in the soil. Hydroxy-Al interlayered minerals were also present in the clay fraction.The amount of smectite in the soils was 31.6 (Shaoxing), 16.5 (Fuyang), and 21.4 (Jinghua) g kg-1; for vermiculite it was 33.3 (Shaoxing), 16.5 (Fuyang), and 8.5 (Jinghua) g kg-1. Smectite was only found in the clay fraction. In contrast, amounts of vermiculite in soil particle size fractions were 3.0～11.4 (sand),2.1～6.0 (coarse silt), 4.6～18.9 (medium silt), 0.9～40.0 (fine silt), and 17.0～108 (clay) g kg-1. The amount of noncrystalline aluminosilicates in the soils in g kg-1 decreased in the order: Shaoxing (2.4) > Jinghua (1.9) > Fuyang (1.7). This study has provided useful mineralogical information that is fundamental in future developmellt of management strategies of the soils.展开更多
Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped gra...Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped grain1 （bsgl）, which produced beak-shaped grains of decreased width, thickness and weight with a loosely interlocked lemma and palea that were unable to close tightly. Starch granules were also irregularly packaged in the bsgl grains. Consistent with the lemma and palea shapes, the outer parenchyma cell layers of these bsgl tissues developed fewer cells with decreased size. Map-based cloning revealed that BSG1 encoded a DUF640 domain protein, TRIANGULAR HULL 1, of unknown function. Quantitative PCR and GUS fusion reporter assays showed that BSG1 was expressed mainly in the young panicle and elongating stem. The BSG1 mutation affected the expression of genes potentially involved in the cell cycle and GW2, an important regulator of grain size in rice. Our results suggest that BSG1 determines grain shape and size probably by modifying cell division and expansion in the grain hull.展开更多
文摘Limited information is available concerning the mineralogy of paddy soils in the southeastern China.Using chemical methods in conjunction with X-ray diffractometry, we studied the mineral composition of three paddy soils: Jinghua (paddy soil on Quaternary red clay), Fuyang (Hapl-percogenic loamy paddy soil), and Shaoxing (gleyic clayey paddy soil). All the soils contained quartz, mica, vermiculite, chlorite and kaolinite, and the distribution of these minerals varied with soil particle size fractions. The clay fraction of the F’uyang and Shaoxing soils also contained smectite. Although X-ray data did not show the presence of smectite in the Jinghua soil, this mineral was identified by the chemical method, suggesting a transitional property of the mineral in the soil. Hydroxy-Al interlayered minerals were also present in the clay fraction.The amount of smectite in the soils was 31.6 (Shaoxing), 16.5 (Fuyang), and 21.4 (Jinghua) g kg-1; for vermiculite it was 33.3 (Shaoxing), 16.5 (Fuyang), and 8.5 (Jinghua) g kg-1. Smectite was only found in the clay fraction. In contrast, amounts of vermiculite in soil particle size fractions were 3.0～11.4 (sand),2.1～6.0 (coarse silt), 4.6～18.9 (medium silt), 0.9～40.0 (fine silt), and 17.0～108 (clay) g kg-1. The amount of noncrystalline aluminosilicates in the soils in g kg-1 decreased in the order: Shaoxing (2.4) > Jinghua (1.9) > Fuyang (1.7). This study has provided useful mineralogical information that is fundamental in future developmellt of management strategies of the soils.
基金supported by grants from the Chinese Academy of Sciences (KSCX2-EW-N-01)the National Natural Science Foundation of China (31100142,31071207)
文摘Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped grain1 （bsgl）, which produced beak-shaped grains of decreased width, thickness and weight with a loosely interlocked lemma and palea that were unable to close tightly. Starch granules were also irregularly packaged in the bsgl grains. Consistent with the lemma and palea shapes, the outer parenchyma cell layers of these bsgl tissues developed fewer cells with decreased size. Map-based cloning revealed that BSG1 encoded a DUF640 domain protein, TRIANGULAR HULL 1, of unknown function. Quantitative PCR and GUS fusion reporter assays showed that BSG1 was expressed mainly in the young panicle and elongating stem. The BSG1 mutation affected the expression of genes potentially involved in the cell cycle and GW2, an important regulator of grain size in rice. Our results suggest that BSG1 determines grain shape and size probably by modifying cell division and expansion in the grain hull.
