[Compensation effect of re-watering after different drought stresses on source-sink metabolism during tuber expansion period of potato.] / 马铃薯块茎膨大期不同程度干旱后复水的源库补偿效应.

The compensation effect of re-watering after drought has been widely reported in various crops during different growth stages. It is considered as an important self-regulation mechanism for plants to resist abiotic stresses and also an efficient utilization of limited water resource. In this study, two rounds of re-watering after drought treatments were carried out during tuber expansion period of potato, to investigate the drought threshold of potato and explore the potential mechanisms of compensation effect with source-sink aspect. We used virus-free plantlets of "Atlantic" potato as experimental materials. Four treatments were included: sufficient water supply (W), re-watering after mild drought (D1-W), re-watering after medium drought (D2-W) and re-watering after severe drought (D3-W). The results showed that potato yield exhibited an over-compensation effect after two rounds of D1-W treatment, with water use efficiency and yield being increased by 17.5% and 6.3%, respectively, compared with the sufficient water supply. D2-W treatment had no significant effect on potato yield, but water use efficiency was increased by 8.4%, indicating a near-equivalent compensation effect. On the contrary, D3-W treatment did not show any compensation effect in yield. In addition, leaf chlorophyll content, net photosynthetic rate, and leaf area were all reduced after drought treatment, indicating a reduction in "source" size and activity. After re-watering, D1-W and D2-W treatments showed over-compensation and compensation effects through improving source supply capacity. Meanwhile, re-watering after moderate drought increased the sink activity through significantly enhancing the activities of key enzymes in tubers (sink), thus increased the average weight of tubers. In conclusion, re-watering after moderate drought stress during potato tuber expansion period had compensation and over-compensation effects on both source and sink, and thus could compensate for the drought-induced yield loss and improve water use efficiency.

Phase II clinical study on the modified DCF regimen for treatment of advanced gastric carcinoma.

BACKGROUND: A phase III trial involving docetaxel, cisplatin, and fluorouracil (DCF) in the treatment of advanced gastric cancer was shown to have superior efficacy compared to cisplatin and fluorouracil alone, but with a high rate of hematologic toxicity. To reduce toxicity while maintaining the efficacy of DCF, we reduced the doses of docetaxel (D) and cis-platinum (CDDP), and administered 5-fluorouracil (5-FU) via a continuous intravenous (CIV) infusion. METHODS: Chemotherapy-naive patients with gastric adenocarcinomas received D (60 mg/m(2) 1 hour on day 1), CDDP (30 mg/m(2) on days 1 and 2), and 5-FU (1500 mg×m(-2)×24 h(-1) CIV on days 1 and 8 every 3 weeks). The primary endpoint was the response rate. RESULTS: Fourteen patients were enrolled. Based on the efficacy evaluation following at least 2 cycles of treatment, there was 7.1% complete remission (CR), 71% partial remission (PR), 14% stable disease (NC/SD), and 7.1% progressive disease (PD). The median survival time was 13 months. Nine patients (64%) had grade III-IV neutropenia, and 4 patients (29%) had grade IV neutropenia, among whom 1 had grade IV neutropenia with grade III nausea and vomiting. CONCLUSION: The modified DCF regimen is highly active and has a favorable toxicity profile in Chinese patients with gastric cancer.

[Effects of planting date and density on population physiological indices of summer corn (Zea mays L.) in central Shaanxi irrigation area].

By using D-saturation optimum design and the methods of crop population physiology, this paper studied the effects of planting date and density on the population physiological indices of summer maize Shandan 8806 and its yield in central Shaanxi irrigation area. The results showed that in the period from 13 June to 22 July, the delay of planting had negative effects on grain yield, dry matter accumulation (DMA), maximum leaf area index (LAImax), net assimilation rate (NAR), leaf area duration (LAD) and crop growth rate (CGR), with larger effects on LAD and CGR than on LAImax and NAR. Within the range of 45 000-65 918 plants . hm (-2), planting density had positive effects on grain yield, DMA, LAImax, LAD and CGR but negative effect on NAR, with larger effects on LAImax, LAD and CGR than on NAR. The effects of planting date were more significant than those of planting density, and thus, Shandan 8806 should be sowed as early as possible. The regressive model based on the population physiological indices indicated that for the high yield of summer maize Shandan 8806, the optimum planting date was from 10 to 20 June, and the optimum planting density was from 57 767 to 71 706 plants . hm(-2).