ABSTRACT
Introduction: The panicle fertilization strategy for japonica and indica rice under wheat straw return (SR) has not been updated, especially on the elaboration of their impacts on spikelet differentiation and degeneration. This study aimed to verify the hypothesis that SR increases spikelet number by reducing spikelet degeneration and to explore the possibility of simplifying panicle fertilization. Methods: In three consecutive years, four varieties of japonica and indica rice were field-grown in Yangzhou, Jiangsu Province, China. Six panicle fertilization rates and split treatments were applied to SR and no straw return (NR) conditions. Results: The results showed that SR promoted rice yield significantly by 3.77%, and the highest yields were obtained under the T2 (split panicle fertilization at the panicle initiation (PI) and spikelet primordium differentiation (SPD) stages) and T1 (panicle fertilization only at the PI stage) treatments, for indica and japonica rice, respectively. Correlation and path analysis revealed that the number of spikelets per panicle was the most attributable to yield variation. SR significantly increased the concentration of alkali hydrolyzable N in the soil 40 days after rice transplantation, significantly increased the nitrogen accumulation per stem (NA) during the SPD-pollen mother cell meiosis (PMC) stage, and increased the brassinosteroids level in the young panicles at the PMC stage. SR also reduced the degeneration rate of spikelets (DRS) and increased the number of surviving spikelets (NSS). The dry matter accumulation per stem was more important to increasing the NA in japonica rice at the PMC stage, whereas NA was more affected by the N content than the dry matter accumulation in indica rice. In japonica rice, panicle N application once only at the PI stage combined with the N released from SR was enough to improve the plant N content, reduce the DRS, and increase the NSS. For indica rice, split application of N panicle fertilization at both the PI and SPD stages was still necessary to achieve a maximum NSS. Discussion: In conclusion, under wheat SR practice, panicle fertilization could be simplified to once in japonica rice with a significant yield increase, whereas equal splits might still be optimal for indica rice.
ABSTRACT
OBJECTIVE: To study basic thyroid stimulating hormone (bTSH) levels impact on outcomes of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in Qinghai. METHODS: Totally 282 cases with IVF cycles and 93 cases with ICSI cycles were studied prospectively, according to bTSH level, patients were divided into four groups. Reproduction rate, clinical pregnancy rate, miscarriage rate and live birth rate were studied among four groups. RESULTS: (1) In 375 cases with IVF/ICSI cycles, bTSH was positively correlated with abortion rate (r = 0.42, P = 0.04), but live birth rate and growing rate showed negative correlations with bTSH (r = -0.42, -0.28; P = 0.04, 0.03). bTSH and the number of eggs, the number of fertilized eggs, the number of embryos, biochemical pregnancy rate, and clinical pregnancy rate were no significant correlation (all P > 0.05). (2) Among women at group of ≤ 1.7, >1.7 and ≤ 2.5, >2.5 and ≤ 3.5, >3.5 mU/L, the implantation rates were 28.7%, 27.3%, 37.7% and 19.2%, live birth rates were 80.9%, 75.0%, 82.7%, and 59.8%, abortion rates were 19.0%, 15.0%, 16.7%, 40.1%; they all showed significant difference (all P < 0.05). Abortion rate in women with high bTSH level was higher than that of women with lower bTSH level, however implantation rate, live birth rate in women with high bTSH level were lower. CONCLUSION: When bTSH level is >3.5 mU/L, the abortion rate were increased, but live birth rate, rate of implantation were decreased.
