Determination of the uptake and translocation of nitrogen applied at different growth stages of a melon crop (Cucumis melo L.) using 15N isotope.

In order to establish a rational nitrogen (N) fertilisation and reduce groundwater contamination, a clearer understanding of the N distribution through the growing season and its dynamics inside the plant is crucial. In two successive years, a melon crop (Cucumis melo L. cv. Sancho) was grown under field conditions to determine the uptake of N fertiliser, applied by means of fertigation at different stages of plant growth, and to follow the translocation of N in the plant using 15N-labelled N. In 2006, two experiments were carried out. In the first experiment, labelled 15N fertiliser was supplied at the female-bloom stage and in the second, at the end of fruit ripening. Labelled 15N fertiliser was made from 15NH415NO3 (10 at.% 15N) and 9.6 kg N ha−1 were applied in each experiment over 6 days (1.6 kg N ha−1 d−1). In 2007, the 15N treatment consisted of applying 20.4 kg N ha−1 as 15NH415NO3 (10 at.% 15N) in the middle of fruit growth, over 6 days (3.4 kg N ha−1 d−1). In addition, 93 and 95 kg N ha−1 were supplied daily by fertigation as ammonium nitrate in 2006 and 2007, respectively. The results obtained in 2006 suggest that the uptake of N derived from labelled fertiliser by the above-ground parts of the plants was not affected by the time of fertiliser application. At the female-flowering and fruit-ripening stages, the N content derived from 15N-labelled fertiliser was close to 0.435 g m−2 (about 45% of the N applied), while in the middle of fruit growth it was 1.45 g m−2 (71% of the N applied). The N application time affected the amount of N derived from labelled fertiliser that was translocated to the fruits. When the N was supplied later, the N translocation was lower, ranging between 54% at female flowering and 32% at the end of fruit ripening. Approximately 85% of the N translocated came from the leaf when the N was applied at female flowering or in the middle of fruit growth. This value decreased to 72% when the 15N application was at the end of fruit ripening. The ammonium nitrate became available to the plant between 2 and 2.5 weeks after its application. Although the leaf N uptake varied during the crop cycle, the N absorption rate in the whole plant was linear, suggesting that the melon crop could be fertilised with constant daily N amounts until 2–3 weeks before the last harvest

Diagnostic Research of CT Combined with Serum CA125 and HE4 in Ovarian Epithelial Malignant Tumor

Objective: To explore the diagnostic value of CT combined with serum CA125 and HE4 in ovarian epithelial malignant tumor. Methods: 156 cases of epithelial ovarian tumors (benign 72 cases, malignant 84 cases) were studied. Detections of CT and serum tumor markers CA125 and HE4 were carried out before operation, the diagnostic results were compared with pathology, for the evaluation of the diagnostic value of CT, CA125, HE4 and combined diagnosis in epithelial ovarian tumors. Results: The positive rates of serum CA125 and HE4 of malignant tumor group were higher than those of benign tumor group; The diagnostic sensitivity of CA125 for malignant tumor was higher than HE4, and the specificity was lower than HE4; the diagnostic accuracy of CA125 combined with HE4 for malignant tumor was higher than CT; the sensitivity, specificity and accuracy of CT combined with serum CA125 and HE4 for malignant tumor was 95.2%, 88.9% and 92.3% respectively, and were higher than CT or tumor markers alone. Conclusion: CT combined with serum CA125 and HE4 shows important value in the diagnosis of ovarian epithelial malignant tumor, which is conducive to early diagnosis and precise staging, and is worthy of promoting in application