Multiple drainage can deliver higher rice yield and lower methane emission in paddy fields in An Giang Province,Vietnam

Paddy and Water Environment - The Mekong Delta produces 55% of Vietnam’s rice (Oryza sativa L.) through double or triple cropping each year. It accounts for a large proportion of...     

Geographic distribution of Waxy gene SNPs and indels in foxtail millet, Setaria italica (L.) P. Beauv.

To elucidate diversity and evolution of the Waxy gene in foxtail millet, Setaria italica, we analyzed sequence polymorphism of Waxy gene in 83 foxtail millet landraces collected from various regions covering the entire geographical distribution of this millet in Europe and Asia. We found a unique geographic distribution pattern at the sequence level of gene haplotypes and also found a large diversity in East Asian landraces. We also found a higher degree of genetic polymorphism in a non-waxy phenotype than in other low amylose types, supporting the hypothesis that low amylose types recently originated from non-waxy type.     

Influence of surface printing materials on the degradability of biodegradable plastic films in soil

Effect of surface printing on the biodegradability of plastic films was studied. Biodegradable films (polybutylene-succinate (PBS)) printed with four kinds of gravure inks were placed in soil for 1 year. The inks consisted of carbon black-pigment with four kinds of resins: poly-(ε-caprolactone) (PCL), nitrocellulose-polyamide blended resin (NT), polyvinyl chloride-vinyl acetate copolymer (V), and nitrocellulose (NC). Degradation of film specimens printed on one side and both sides as well as the control film without printing was monitored every 3 months by collecting sample specimens for the measurement of weight loss. No appreciable degradation was observed until 6 months after placement in soil for the control specimens and until 9 months for the printed specimens. And the degradation of the PCL- and NC-printed specimens with one-side printing and V-printed specimens with both-side printing was significantly slower than that of the control specimens without printing after 9-month placement at p < 0.05. Only after 12 months of placement, was the degradation significantly faster for the specimens printed on one side than for those printed on both sides except of the specimens printed with NC. There was no difference in biodegradability among PCL, NT, NC, and V resins. Specimens printed on both sides did not show any appreciable weight loss after 1 year in soil (percentage of maintenance of weight exceeding 98%). Microscopic observation indicated that the degradation mainly proceeded from the non-printed side to the printed side cross-sectionally.     

Denaturing gradient gel electrophoresis analysis of gut bacterial community for the Japanese earthworms

The gut bacterial community structure for Pheretima hilgendorfi and P. heteropoda (Family Megascolecidae), and Allolobophora japonica (Family Lumbricidae) collected from agricultural grasslands in Japan was analyzed by denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S rRNA gene fragments (PCR-DGGE) and compared with those in the surrounding soils. Denaturing gradient gel electrophoresis (DGGE) profiles indicated that each earthworm species had their own specific bacterial communities, and multidimentional scaling analysis grouped the DGGE profiles into three groups: gut samples from P. hilgendorfi and P. heteropoda, gut samples from A. japonica and samples from the surrounding soils. Nine dominant bands were identified by their direct sequencing and cloning. Major three bands from P. hilgendorfi and P. heteropoda were closely related to Bacillus species belonging to the phylum Firmicutes. Major four and two bands from A. japonica were closely related to the phyla Proteobacteria and Bacteroidetes, respectively.     

Use of soil color meter for aqueous iron and ammonium measurements

Abstract

In this paper, we proposed a new approach for on-site colorimetric analysis of ferrous ions (Fe²⁺) and ammonium-nitrogen (NH₄ ⁺-N) using a soil color meter as an alternative method to conventional spectrophotometry. The soil color meter we used can express solution color numerically on the basis of L*a*b* color space. After coloring of water by the 1, 10 phenanthroline method and the Indophenol blue method, the color of solution was measured by the soil color meter. A linear relationship between Fe²⁺ and a* or b* values, and systematic change of NH₄ ⁺-N with L* value, enable us to make a calibration curve. The Fe²⁺ and NH₄ ⁺-N concentrations in groundwater samples (Fe²⁺: 0.3–1.3 mg L^?1; NH₄ ⁺-N: 0.02–0.62 mg L^?1) determined by the proposed method agreed well with those determined by conventional spectrophotometry with the difference being ± 0.05 mg L^?1 and ± 0.02 mg L^?1, respectively. Since a similar apparatus is widely used in the soil science field, this technique would facilitate field surveys.     

Salinity and Defoliation Effects on Soybean Growth

An experiment was conducted to determine if salinity stress alters the response and tolerance of soybean to defoliation. Four soybean [Glycine max(L.) Merr.] cultivars (‘Tachiutaka,’ ‘Tousan 69,’ ‘Dare’ and ‘Enrei’) in a growth chamber were exposed to two salinity treatments (0 and 40 mM NaCl) and two defoliation treatments (with and without defoliation). The interactive effects of salinity stress and defoliation on growth rate, leaf expansion, photosynthetic gas exchange, and sodium (Na⁺) accumulation were determined. The decrease in growth rate resulting from defoliation was more pronounced in plants grown under salinity stress than in those grown without the stress. Without salinity stress, defoliated plants of all four cultivars had leaf-expansion similar rates to those of the undefoliated ones, but the photosynthetic rates of their remaining leaves were higher than those of undefoliated plants. However, with salinity stress, defoliated ‘Tachiutaka’ and ‘Tousa 69’ had lower leaf expansion and photosynthetic rates than undefoliated plants. For cultivars ‘Dare’ and ‘Enrei,’ the defoliated plants had leaf-expansion rates similar to undefoliated ones, but the photosynthetic rate of the remaining leaves did not increase. Except for cultivar ‘Dare,’ defoliated plants grown under salinity stress had higher Na⁺ accumulation in leaves than undefoliated ones, and this result may be related to slow leaf expansion and photosynthesis. Salinity stress negatively affects soybean response and tolerance of defoliation, and the effects varied according to the salt tolerance of the cultivar.     

Characterizing nicotianamine aminotransferase: Improving its assay system and details of the regulation of its activity by Fe nutrition status

Under iron deficient conditions, graminaceous plants secrete mugineic acid family phytosiderophores (MAs) from their roots to dissolve sparingly soluble iron compounds in the rhizosphere, and take up iron in the form of an Fe³⁺-MAs complex (Takagi 1976). A good correlation has been reported between the tolerance of Fe-deficiency and the amount of secreted MAs (Takagi 1993). Therefore, by using the genes involved in MAs biosynthesis, molecular breeding might produce transgenic plants tolerant to Fe-deficiency with a high level of MAs secretion. The biosynthetic pathway of MAs from L-methionine has been clarified (Fig. 1) and the enzymes participating in this process are now being investigated to isolate the genes responsible. Nicotianamine aminotransferase (NAAT) catalyzes the amino group transfer between nicotianamine (NA) and 2-oxoglutaric acid (Fig. 1). In order to purify NAAT, enzyme assay methods for NAAT have been developed and modified (Shojima et al. 1990; Ohata et al. 1993; Kanazawa et al. 1994). Some characteristics of NAAT have been reported using these enzyme assay methods (Kanazawa et al. 1994, 1995). Here, we further investigate some characteristics of this enzyme to improve the enzyme assay method, namely 1) the effect of K⁺ and Mg²⁺ on NAAT activity in vitro, and 2) the direct influence of MAs, Fe³⁺, and Fe²⁺ on NAAT activity. In addition, based on these results, the induction of enzyme activity by Fe-deficiency and suppression of the activity by Fe-resupply was investigated, by applying the new enzyme assay method.     

Compost Research Runs “Hot” and “Cold” at La Trobe University

? Careful monitoring of the composting process — physically, chemically and biologically — enables managers to determine key nutritional and ecological factors vital to production of a quality compost. At La Trobe University, trials compared composts which achieve high temperature (80° C) with those controlled at moderate thermophilic temperatures (45 — 55° C) to demonstrate whether the hot phase is essential or whether composts of equal nutritional status can be produced by processing at lower temperatures.     

Pyogenic meningitis and trigeminal neuritis secondary to periodontogenic paranasal sinusitis in a red deer (Cervus elaphus)

An adult female red deer died of a severe seizure and dysbasia. Postmortem computed tomography (CT) and magnetic resonance imaging (MRI) were performed. On CT, deciduous right maxillary second and third premolar teeth were observed, and the right infraorbital canal was disrupted. MRI showed that the right trigeminal nerve was enlarged and the right subarachnoid cavity was occupied by fluid and gas. On gross examination, the right paranasal sinus, swollen muscles of the orbit and tonsils, right trigeminal nerve, and right cerebrum surface contained a yellowish-white, cheese-like pus. Based on these findings, the deer was believed to have developed pyogenic meningitis caused by a neuropathic infection secondary to periodontogenic paranasal sinusitis.     

农业机械全方位视觉定位系统的定位算法

农业机械全方位视觉定位系统根据标识方位角角度估算传感器相对于标识坐标系的绝对位置,包括系统校正、除噪、标识特征提取、方位角度估算和定位算法,其中定位算法是实现农业机械全方位视觉定位系统的关键部分。该文主要研究了4个标识和3个标识的定位算法,并通过室外30m×30m平地上的定点试验和传感器倾斜试验验证定位精度及传感器倾斜对定位精度的影响。试验结果表明,试验点坐标的估算值与实测值之间距离的均方根误差与平均绝对误差分别为14.75和14.06cm,最大绝对误差为25.72cm;倾斜角度越大,对定位精度的影响越大。研究表明本文定位算法是可行的,且算法简单、运行速度快;实用中当传感器倾斜角度大于5°或者凹凸不平明显的作业环境中,有必要考虑传感器倾斜造成的定位误差的补偿。