Wheat egg in vitro fusion with wheat and green bristlegrass sperm.

SummaryIsolated gametes can be used to investigate fertilization mechanisms, and probe distant hybridization between different species. Pollen grains of wheat and Setaria viridis are tricellular, containing sperm cells at anthesis. Sperm from these plants were isolated by breaking open pollen grains in a osmotic solution. Wheat ovules were digested in an enzyme solution for 20 min, and then transferred to an isolation solution without enzymes to separate egg cells from ovules. The fusion of wheat egg cells with wheat and S. viridis sperm was conducted using an electro-fusion apparatus. Under suitable osmotic pressure (10% mannitol), calcium concentration of 0.001% (CaCl2·2H2O), and a 30-35 V alternating electric field for 15 s, egg cells and sperm adhered to each other and became arranged in a line. Electroporation of the plasma membrane of egg cells and sperm using a 300-500 V direct-current electric field (45 µs amplitude pulse) caused them to fuse.

Calcium controls the formation of vacuoles from mitochondria to regulate microspore development in wheat.

Potassium antimonite was used to investigate the localisation of calcium in developing wheat anthers to examine the relationship between Ca2+ and pollen development. During anther development, calcium precipitate formation increased in anther wall cells prior to microspore mother cell meiosis and appeared in microspores, suggesting the presence of a calcium influx from anther wall cells into the locule. Initially, the precipitates in microspore cytoplasm primarily accumulated in the mitochondria and destroyed their inner membranes (cisterns) to become small vacuoles, which expanded and fused, ultimately becoming a large vacuole during microspore vacuolisation. After microspore division and large vacuole decomposition, many calcium precipitates again accumulated in the small vacuoles, indicating that calcium from the large vacuole moved back into the cytoplasm of bicellular pollen.

[Stem characteristics of different wheat varieties and its relationship with lodging-resistance.] / ä¸åŒå°éº¦å“ç§èŒŽç§†ç‰¹æ€§åŠå ¶ä¸ŽæŠ—å€’æ€§çš„å ³ç³».

Taking four outstanding varieties Aikang 58, Zhoumai 18, Yumai 49 and Bainong 418 from Huanghuai wheat area as test objects, the lodging-resistance traits of different varieties at different growth stages were investigated by combining field and laboratory methods. The results showed that stem mechanical strength was at a high level between flowering and 20 days after flowering, declined significantly in 30 days after flowering. The lodging index was minimal in flowering period, maximal in 30 days after flowering, and was at an intermediate level in the other two periods. Correlation analysis showed that culm mechanical strength was significantly negatively correlated with the height of gravity, and significantly positively correlated with cellulose and lignin contents at the flowering, lodging index was significantly positively correlated with the internode length, plant height and height of gravity, but significantly negatively correlated with cellulose and lignin contents. Ten days and 20 days after flowering, the culm mechanical strength was negatively correlated with the internode length, plant height and height of gravity, and significantly positively correlated with stem diameter, cellulose content, hemicelluloses content and lignin content, while the lodging index was just the opposite. Thus, making lodging-resistance related stem characteristics at each stage clear, could provide a basis for breeding lodging-resistance and high yield varieties in Huanghuai wheat area.

[Effects of harvest date on quality of BNS hybrid wheat flour and steamed bread].

Three wheat hybrids derived from the BNS male sterile line were used to study the effect of harvest time on gluten content, dough rheological properties, starch pasting properties of wheat flour and the quality of steamed bread. Each of the three hybrids was harvested at May 27, May 31 and June 4, respectively. The results showed that the flour quality of BNS hybrids was affected by harvest time to some extents, and the best harvest time varied among the different hybrids. For Baiza 1, Baiza 2 and Baiza 3, the best harvest time was May 27, May 27 and June 4, respectively. Both the flour quality and the comprehensive score and taste of steamed bread were the best for the hybrids harvested at these dates. Moreover, Baiza 2 was suited to make steamed bread and noodle when harvested on May 27.

[Effects of sprinkler irrigation on the plant nitrogen accumulation and translocation and kernel protein content of winter wheat].

Taking wheat cultivar Bainong AK58 as test material, a field experiment was conducted to study the plant nitrogen accumulation and translocation and kernel protein content of winter wheat under sprinkler irrigation and surface irrigation, aimed to understand the differences in the nitrogen metabolism characteristics of winter wheat under different irrigation regimes. At booting stage, no significant difference was observed in the total amount of plant nitrogen accumulation between sprinkler irrigation and surface irrigation; while from booting stage to maturing stage, the total amount of plant nitrogen accumulation under sprinkler irrigation was significantly higher. Under sprinkler irrigation, the translocation amount and contribution rate of the nitrogen stored in leaf, glume, stem and sheath at pre-anthesis to the kernel increased, while the contribution rate of the assimilated nitrogen after anthesis to the kernel nitrogen declined. Both the relative protein content and the total protein yield in the kernel increased significantly under sprinkler irrigation. In conclusion, sprinkler irrigation could significantly regulate the nitrogen translocation and kernel protein accumulation of winter wheat.

[Effects of 5-aminolevulinic acid on winter wheat dry matter accumulation after anthesis and flag leaf senescence].

Taking wheat cultivar Bainong AK58 as test material, a field experiment was conducted to study the effects of different concentration 5-aminolevulinic acid (ALA) (0,10, 30 and 50 mg x L(-1)) applied at initial heading stage on the post-anthesis dry matter accumulation and flag leaf senescence of the cultivar. Applying 10-50 mg x L(-1) of ALA benefited the dry matter accumulation, with its total amount at maturing stage being significantly higher than that of the control (0 mg x L(-1) ALA). 10-50 mg x L(-1) of ALA had no significant effects on the distribution of accumulated dry matter in leaf, stem and sheath, and grain, but increased the contribution of the dry matter to grain yield. 10-50 mg x L(-1) of ALA increased the leaf area index at milky and dough stages, but had no effects on it at flowering stage. After treated with 10-50 mg x L(-1) ALA, the leaf SPAD value and net photosynthetic rate from anthesis to milky stage were significantly higher, and the MDA content and relative electric conductivity at later grain-filling stage were lower, compared with those of the control. Applying 10-50 mg x L(-1) of ALA increased the grain number per spike, 1000-grain mass, and grain yield significantly, with the best effect when applying 30 mg x L(-1) ALA.