Estimation of Nitrogen Fertilizer Use Efficiency in Dryland Agroecosystem

A field trial was carried out to study the nitrogen fertilizer recovery by four crops in succession in manurial loess soil in Yangling. The results showed that the nitrogen fertilizer not only had the significant effects on the first crop , but also had longer residual effects, even on the fourth crop. The average apparent nitrogen fertilizer recovery by the first crop was 31.7%, and the accumulative nitrogen recovery by the 4 crops was high as 62.3%, and the latter was double as the former. It is quite clear that the nitrogen fertilizer recovery by the first crop was not reliable for estimating the nitrogen fertilizer unless the residual effect of nitrogen fertilizer was included.

Effects of the Alternatively Interspaced Furrow Irrigation on Maize Root Distribution and Grain Yield, and Its Water-saving Benefits

A test of three types of irrigation was carried out in the oasis area of the arid region in Minqin County for the study of the effects of the controllable alternatively root-partitioned irrigation (CARI) on corn ( Zea mays L. ) growth, root distribution, and the water-saving benefits. The research results showed that the alternatively interspaced furrow irrigation (AIFI) could significantly increase the water use efficiency of irrigation. The water use efficiency of the FI was 2.6 - 2.7kg/m3 and that of the AIFI reached more than 4.0kg/m3. The total water use efficiency of the AIFI reached more 2.98 kg/m3. Although the kernel yields of the AIFI remained to be more than 8000kg/ha in the two years, the irrigated water amounts declined from 3250m3/ha to 1575m3/ha. Thus the AIFI could save irrigation water by more than 33.3%, but did not severely reduce the corn yields. The wetting-drying alternation of the AIFI could stimulate the root growth, increase the root density and enhance the balanced root distribution; the dryness of partial root zone formed by the AIFI stimulated the roots to form the root signals to regulate the stomata openness, reduce the evaporation through the clearances among the plants, raise the evaporation efficiency and save the irrigation water.

Response of Tomato Plants to a New Application Method of Polyolefin-Coated Fertilizer

The response of tomato （Lycopersicon esculentum） plants basically fertilized with 0.3 g N per plant of compound fertilizer with a N：P2O5：K2O ratio of 20：10：20 to sticks of polyolefin-coated fertilizer （POCF） （LongT0 with a N：P2Os：K2O ratio of 14：12：14） applied 23 d after transplanting was investigated using rooting boxes in the greenhouse. The results at 26 and 40 d after stick fertilizer treatment showed that the use of the stick fertilizer greatly increased the production of many new fine roots from the tomato plants. Compared to the unfertilized control, root length and root length density in the stick fertilizer treatment increased by 3.6-6.7 fold. In the soil zones near the stick fertilizer, root weight and root mass density were also significantly higher for the stick fertilizer treatment. Additionally, the use of the stick fertilizer increased the N, P and K concentrations in the leaves and stems of the tomato plants. The new fine roots growing near the stick fertilizer not only absorbed more nutrients and translocated them to the shoots, but also contained more nutrients within themselves. The soil ammonium and nitrate N data showed that N released from the stick fertilizer played a major role in inducing the production of new fine roots. These results indicated that stick fertilizer could be used as an alternative to the co-situs application technique to change and control the root distribution of crops as well as to increase the potential capacity of roots for water and nutrient absorption.

Analysis of E^(rns)Genes Nucleotide Sequence of Prevalent Virulent Strains of Hog Cholera Virus

The E^(rns)gene of five prevalent virulent strains and one C-strain of Hog Cholera Virus were amplified by reverse transcription(RT).The amplified fragments were cloned and sequenced.Comparison and analysis were made on the nucleotide sequence and the amino acid sequence of five prevalent virulent strains of HCV was deduced.The nucleotide homology was from 91%to 98%;the homology of amino acid was from 94%to 98%.The nucleotide homology of C-strain virus from cell cultured and five prevalent virulent strains of HCV was 83%to 84%.The amino acid homology was from 89%to 91%.

Sequence analysis of the gene correlated with cytoplasmic male sterility (CMS) in rape-seed (Brassica napus) Polima and Shaan 2A

orf224 is a CMS-related mitochondrial gene discovered in Polima cytoplasm. Shaan 2A CMS line is the parent of the first rapeseed hybrid cultivar Qinyou No. 2 that has been grown in many regions of China. In this work, genomic DNA of Polima CMS line and Shaan 2A CMS line were used as templates, two primers of specific oligonucleo-tides at 5’ and 3’ ends were used, PCR was performed, the amplification fragments were cloned into pGEM-T Easy vectors and DNA sequences were determined. The CMS-associated gene, orf224-1 present in Shaan 2A CMS line, has a sequence highly homologous to the orf224 of the Polima CMS line, except for one nucleotidc at position +398. There were only one base (AAC→AGC) and one amino acid (Asn→Ser) differences between the two. The homologies of the two sequences in nucleotide and amino acid were 99.9% and 99.6%, respectively. It is concluded that orf224 in Polima CMS line and orf224-1 of Shaan 2A CMS line are the allele at the same locus in mitochondria.

Seasonal variations in leaf capturing of particulate matter, surface wettability and micromorphology in urban tree species

The seasonal changes in leaf particulate matter （PM） accumulation, surface wettability and micromor- phology in urban tree species, including Sophorajaponica （S. japonica）, Platanus acerifolia （P. acerifolia） and Cedrus deodara （C. deodara）, were studied during a single growing season. The three species showed distinct seasonal trends in PM accumulation, increasing from spring to autumn （or winter） even during the rainy season, but at different rates. During the study, the leaf PM retention amount ofP acerifolia, a species with ridged leaf surfaces, was significantly higher than that of S. japonica and C. deodara, species with waxy leaf surfaces. The contact angles of water droplets on leaves decreased with leafage except on the abaxial surface orS.japonica, which remained non-wettable or highly non-wettable throughout the growing season; the decrease in the contact angle on adaxial surface of S. japonica was greater when compared with P acerifolia and C. deodara. A significant and negative relationship existed between leaf PM retention amounts and contact angles on adaxial surface of leaves of all three species. The increase in wettability, probably caused when epicuticular wax was destroyed by mechan- ical and chemical abrasion, seemed to be the main factor leading to seasonal variations in leaf PM accumulation.

Crystal Structure and Bioactivity of Complex [Gd（C10H9N2O4）（C10H8N2O4）（H2O）3]2·phen·4H2O

A novel gadolinium（Ⅲ） complex with N-（2-propionic acid）-salicyloyl hydrazone （C10H10N2O4, H3L） and 1,10-phenanthroline （C12H8N2, phen） was prepared and characterized. The crystal structure of [Gd（H2L）（HL）- （H2O）3]2·phen·4H2O was determined by X-ray single crystal diffractometry. The crystal complex crystallizes in the triclinic system with space group P-1. There are two 9-coordinated structure units in every complex molecule, in which Gd（Ⅲ） is coordinated by two tridentate ligands （H2L and HL forms） and three water molecules and both the structural units take a distorted monocapped square antiprism. There is a free 1,10-phenanthroline connecting with coordinated water by hydrogen bonds in the crystal. The bioactivity tests indicate that the complex is an inhibitor against three bacteria.