[Effects of irrigation at flowering stage on soil nutrient and root distribution in wheat field]. / å°éº¦å¼€èŠ±æœŸçŒæ°´å¯¹åœŸå£¤å »åˆ†åŠæ ¹ç³»åˆ†å¸ƒçš„å½±å“.

To provide theoretical support the full use of water and fertilizer resources for wheat, we explored the effects of irrigation on wheat yield, plant and soil nutrient distribution during flowering period and its relationship with root characteristics. We set up two treatments by using the 2 m deep soil column cultivation method with irrigation during flowering (T1) and no irrigation during flowering (T2), with the drought-resistant and high-yield cultivar Luomai 28 (LM28) and the high photosynthetic efficiency cultivar Bainong 207 (BN207) as materials. We measured contents of nitrogen, phosphorus and potassium in plants and soils, as well as the characteristics of soil roots. The results showed that ammonium, available phosphorus, and available potassium were mainly distributed in 0-80 cm soil layer, and that nitrate was mainly distributed in soil layer below 80 cm during wheat harvest. Irrigation at anthesis stage promoted wheat to absorb ammonium, available phosphorus and available potassium from the upper layer of soil and nitrate nitrogen from the lower layer but did not aggravate the deep leaching of nitrate. The root of wheat mainly concentrated in 0-60 cm soil layer and decreased with increasing soil depth. Dry matter accumulation, total nitrogen and total phosphorus were mainly distributed in wheat grains at maturity, while total potassium was mainly distributed in stems. Irrigation at anthesis stage significantly increased the 100-grain weight of wheat, and consequently the yield. Root morphology was negatively correlated with soil nitrate in 0-40 cm soil layer, positively correlated with soil ammonium in 80-100 cm soil layer and soil available phosphorus in 0-100 cm soil layer. Irrigation at anthesis stage promoted the full absorption of soil nutrients by roots at late filling stage, delayed the senescence of flag leaves after flowering, prolonged the functional period of transporting nutrients from vegetative organs to reproductive organs, leading nutrients in vegetative organs more fully transported to grains, increasing grain weight and yield.

[A study on introduction of chitinase gene and beta-1,3-glucanase gene into restorer line of dian-type hybrid rice (Oryza sativa L.) and enhanced resistance to blast (Magnaporthe grisea)].

Plasmid pBLGC containing chitinase gene from Phaseolus limensis and beta-1,3-glucanase gene from Nicotiana tabacum was bombarded into the restorer line "Nan29" of Dian-type hybrid rice (Oryza sativa L. ssp. japonica) from Yunnan province of South-west China. 93 regenerants were obtained from the calli that were resistant to G418 (100 to 150 mg/L) on NB medium. Using beta-1,3 glucanase gene as the probe, 17 of the regenerants were identified to be transgenic lines by dot blotting and the foreign genes construction were integrated into the genomes of T1 lines by Southern blotting hybridization. Two foreign genes were inherited stably to T4 generation according to PCR results of the lines. The resistance to rice blast of six transgenic lines were evaluated by inoculating four violent biological races of Magnaporthe grisea from Yunnan province and inducing the disease in the field. The results indicated that the resistance to rice blast of transgenic lines were enhanced to varying degrees compared with the receptor line and the transgenic lines could be used in rice blast resistant breeding.

[The germinating characters of the transgenic rice seeds in the stress condition of antibiotic G418 and their application in crop breeding].

The seeds of transgenic rice line D2-1-2 and the receptor cultivar Zhonghua No.9 were germinated on the stress condition of the antibiotic G418. The number of taking root seed, the length of root and the length of shoot of two used materials were checked in different concentrations of the antibiotic G418, but the ratio of germinating seed was not affected. At the 100 mg/L level of G418, the transgenic line D2-1-2 could take longer root (mean 1.45 cm) but Zhonghua No.9 very short (mean 0.27 cm). 88.46% of the total long-root (<0.5 cm) seeds selected from the mixing population of D2-1-2 and Zhonghua No.9 at the 100 mg/L level of antibiotic G418 were real transgenic ones.