[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.

[Effects of row spacing and sowing rate on vertical distribution of photosynthetically active radiation, biomass, and grain yield in winter wheat canopy.] / è¡Œè·å’Œæ’­ç§é‡å¯¹å†¬å°éº¦å† å±‚å ‰åˆæœ‰æ•ˆè¾å°„åž‚ç›´åˆ†å¸ƒã€ç”Ÿç‰©é‡å’Œç±½ç²’äº§é‡çš„å½±å“.

To clarify the effects of row spacing and sowing rate on the vertical distribution of canopy PAR, biomass, and grain yield in winter wheat, a field experiment was conducted without increa-sing water and fertilizer input. There were two row spacing modes, R1 (equal spacing, 20 cm+20 cm) and R2(wide and narrow row spacing, 12 cm+12 cm+12 cm+24 cm), and three sowing rates, D1 (low, 120 kg·hm-2), D2 (medium, 157.5 kg·hm-2), D3 (high, 195 kg·hm-2). The canopy photosynthetically active radiation (PAR) interception and utilization rate in different heights, population photosynthetic capacity, biomass, and grain yield were measured during the main growth stages of winter wheat. The results showed that both total PAR interception and upper layer PAR interception of winter wheat canopy under R1 treatment were significantly higher than those in R2 treatment, but those of the middle layer and lower layer were higher in R2 than in R1, and with significant difference in the middle layer. From flowering to maturity, the photosynthetic potential (LAD), population photosynthetic rate (CAP), PAR conversion rate, and utilization rate in R2 were all significantly higher than those in R1 under the same sowing rate, with the highest value under R2D2 treatment. With the increasing sowing rate, the population biomass (BA) and leaf biomass (BL) at different layers increased, but the individual biomass (BP) showed an opposite trend. Under the same sowing rate, BA, BL and BP in R2 were higher than that in R1 after the flowering stage. Among them, BA and BP had significant difference in row spacing treatments at the maturity stage, with significant difference between the two row spacing treatments being observed in BL of the middle and lower layers under D2 and D3 sowing rates. The spike number, grain number per spike, 1000-kernel weight, and grain yield of winter wheat among different treatments were the highest in R2D3, R2D1, R2D1, and R2D2, respectively. The 1000-kernel weight, grain number per spike and grain yield in R2 treatment were significantly higher than R1. In summary, the PAR interception in the middle and lower layers of winter wheat canopy was improved by changing row spacing, with positive consequence on the photosynthetic capacity of individual plant and population, PAR utilization and transformation efficiency, which finally increased biomass and grain yield. Therefore, optimizing the field structure and shaping the ideal population photosynthetic structure should pay more attention during the high-yield cultivation of winter wheat. Making full use of light resources per unit land area and excavating the photosynthetic production potential of crops were also critical to achieve high yield and efficiency. In this experiment, the population photosynthetic capacity, photosynthetic effective radiation utilization rate, and yield were the highest under the treatment of R2D2.

[Effects of tillage and nitrogen application rate on soil nitrogen transformation and yield in a winter wheat/summer maize multiple cropping system]. / 耕作方式与施氮量对小麦-çŽ‰ç±³å¤ç§ç³»ç»ŸçŽ‰ç±³å­£åœŸå£¤æ°®ç´ è½¬åŒ–åŠäº§é‡çš„å½±å“.

In the winter-wheat and summer-maize multiple cropping system in lime concretion black soil of Huanghuaihai Plain, the effects of three tilling methods (conventional tillage, rotary tillage, subsoiling tillage) in wheat season coupling with three nitrogen treatments (120 kg·hm-2, 225 kg·hm-2, 330 kg·hm-2) before maize sowing on the activities of microorganisms and enzymes re-lated nitrogen transformation, and inorganic nitrogen content in the rhizosphere soil during the main growth stages of maize, as well as the yield were investigated. The results showed that the rotary tillage had the highest ammonification intensity, and the more nitrogen was put in, the higher were the activities of microorganisms and enzymes related to soil nitrogen transformation. The activities of nitrification, denitrification and urease of subsoiling tillage was significantly higher than those of conventional and rotary tillage. Furthermore, in subsoiling tillage treatment, increasing nitrogen fertili-zer could promote soil nitrogen transformation while excessive nitrogen input inhibited soil nitrogen transformation, though the latter had higher yield and soil inorganic nitrogen content. The treatment of subsoiling tillage coupling with 225 kg·hm-2 nitrogen, was best for soil nitrogen transformation while the treatment of subsoiling tillage coupling with 330 kg·hm-2 nitrogen, had the highest corn yield.

UPLC-QTOF analysis reveals metabolomic changes in the flag leaf of wheat (Triticum aestivum L.) under low-nitrogen stress.

Wheat is one of the most important grain crop plants worldwide. Nitrogen (N) is an essential macronutrient for the growth and development of wheat and exerts a marked influence on its metabolites. To investigate the influence of low nitrogen stress on various metabolites of the flag leaf of wheat (Triticum aestivum L.), a metabolomic analysis of two wheat cultivars under different induced nitrogen levels was conducted during two important growth periods based on large-scale untargeted metabolomic analysis using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF). Multivariate analyses-such as principle components analysis (PCA) and orthogonal partial least square discriminant analysis (OPLS-DA)-were used for data analysis. PCA yielded distinctive clustering information among the samples, classifying the wheat flag samples into two categories: those under normal N treatment and low N treatment. By processing OPLS-DA, eleven secondary metabolites were shown to be responsible for classifying the two groups. The secondary metabolites may be considered potential biomarkers of low nitrogen stress. Chemical analyses showed that most of the identified secondary metabolites were flavonoids and their related derivatives, such as iso-vitexin, iso-orientin and methylisoorientin-2″-O-rhamnoside, etc. This study confirmed the effect of low nitrogen stress on the metabolism of wheat, and revealed that the accumulation of secondary metabolites is a response to abiotic stresses. Meanwhile, we aimed to identify markers which could be used to monitor the nitrogen status of wheat crops, presumably to guide appropriate fertilization regimens. Furthermore, the UPLC-QTOF metabolic platform technology can be used to study metabolomic variations of wheat under abiotic stresses.

Changing patterns of Serum CEA and CA199 for Evaluating the Response to First-line Chemotherapy in Patients with Advanced Gastric Adenocarcinoma.

BACKGROUND: This study was designed to investigate the value of CEA and CA199 in predicting the treatment response to palliative chemotherapy for advanced gastric cancer. MATERIALS AND METHODS: We studied 189 patients with advanced gastric cancer who received first-line chemotherapy, measured the serum CEA and CA199 levels, used RECIST1.1 as the gold standard and analyzed the value of CEA and CA199 levels changes in predicting the treatment efficacy of chemotherapy. RESULTS: Among the 189 patients, 80 and 94 cases had increases of baseline CEA (≥5 ng/ml) and CA199 levels (≥ 27U/ml), respectively. After two cycles of chemotherapy, 42.9% patients showed partial remission, 33.3% stable disease, and 23.8% progressive disease. The area under the ROC curve (AUC) for CEA and CA199 reduction in predicting effective chemotherapy were 0.828 (95%CI 0.740-0.916) and 0.897 (95%CI 0.832-0.961). The AUCs for CEA and CA199 increase in predicting progression after chemotherapy were 0.923 (95%CI 0.865-0.980) and 0.896 (95%CI 0.834-0.959), respectively. Patients who exhibited a CEA decline ≥24% and a CA199 decline ≥29% had significantly longer PFS (log rank p=0.001, p<0.001). With the exception of patients who presented with abnormal levels after chemotherapy, changes of CEA and CA199 levels had limited value for evaluating the chemotherapy efficacy in patients with normal baseline tumor markers. CONCLUSIONS: Changes in serum CEA and CA199 levels can accurately predict the efficacy of first-line chemotherapy in advanced gastric cancer. Patients with levels decreasing beyond the optimal critical values after chemotherapy have longer PFS.

Antitumor activity of chloroquine in combination with Cisplatin in human gastric cancer xenografts.

PURPOSE: To investigate the antitumor activity and mechanism of chloroquine (CQ) in combination with cisplatin (DDP) in nude mice xenografted with gastric cancer SGC7901 cells. MATERIALS AND METHODS: 35 cases of gastric cancer patients with malignant ascites were enrolled and intraperitoneal cisplatin injection was performed. Ascites were collected before and 5 days after perfusion for assessment of autophagy levels in cancer cells. In addition, 24 tumor-bearing mice were randomly divided into control, DDP, CQ and CQ + DDP groups. RESULTS: In 54.3% (19/35) of patients the treatment was therapeutically effective (OR), 5 days after peritoneal chemotherapy, 13 patients had the decreased ascites Beclin-1 mRNA levels. In 16 patients who had NR, only 2 cases had decreased Beclin-1 (P=0.001). Compared with the control group, the xenograft growth in nude mice in the DDP group was low, and the inhibition rate was 47.6%. In combination with chloroquine, the inhibition rate increased to 84.7% (P<0.01). The LC3-II/I ratio, and Beclin1 and MDR1/P-gp expression were decreased, while caspase 3 protein levels increased (P<0.05). CONCLUSIONS: Antitumor ability of cisplatin was associated with autophagy activity and chloroquine can enhance chemosensitivity to cisplatin in gastric cancer xenografts nude mice.