不同尺寸栽培袋番茄营养基质栽培效果研究

以无纺布为番茄营养基质栽培袋材料，采用威曼83-06 番茄品种，研究了3 种不同尺寸栽培袋32 cm×25 cm（G1）、
55 cm×32 cm（G2）、60 cm×25 cm（G3）对袋培番茄植株生长、产量及品质的影响。结果表明：32 cm×25 cm 的无纺布栽培
袋中加5.5 L 的基质适合为期4 个月的秋冬茬番茄袋式栽培，其地上部干质量和地下部干质量以及番茄单株产量、平均单果
质量均高于G2、G3 处理，并且其果实品质优于G2、G3 处理。     

Soil phosphorus fractions in aggregate size classes in southwestern China

The build‐up of topsoil phosphorus (P) through excess fertilizer application can increase P losses in run‐off leading to negative impacts on aquatic ecosystems. To better understand the risk of P losses, the fractions of soil P in four aggregate size classes were quantified for two vegetable production sites (<10 and >25 yrs) and a conservation buffer site (8 yrs) in southwestern China. Sequential extraction methods of inorganic P (Pi) and organic P (Po) were carried out on samples from Nitisol and Gleysol soils from 0 to 5 cm and 5 to 10 cm depths. On average, soil Pi concentrations exceeded Po concentrations threefold, primarily in the bioavailable Pi fractions (labile Pi, loosely bound Pi and non‐occluded Pi). Soil Po fractions and bioavailable Pi fractions were significantly greater under the >25 yrs field than in the <10 yrs field. The conversion of fields under vegetable production to forested buffer substantially decreased the levels of the bioavailable Pi and labile Po in the Gleysol after 8 yrs. Soil macro‐aggregates (>0.25 mm) had greater concentrations of bioavailable Pi fractions and of labile and moderately labile Po than did micro‐aggregates and silt and clay size components. Although more P was stored in recalcitrant P forms, a larger percentage of all P fractions was found in macro‐aggregates in these soils. Small active P‐enriched aggregates potentially intensify export of P from the vegetable soils by run‐off, and therefore, management practices must be optimized to enhance agricultural P efficiencies.     

磁化海水在对虾育苗中的应用研究

经过磁场处理的海水;应用在中国对虾人工育苗和短期养成的研究中,产生了良好的生物效应,使用1600G、2400G、3000G三种磁感应强度的磁化装置处理的海水,对于仔虾的成活率都有较明显的提高,平均提高17.90％;在对虾短期养成(室内)中,使成活率和体长都比对照高,平均提高51.88％和10.56％。这主要因为     

High Protein Soybean Performance Under Field Conditions

An early maturing soybean [ Glycine max (L.) Merr.] cultivar has been developed with substantially higher seed protein concentration than previously available cultivars. The objectives of this study were to evaluate the performance of the high protein line under field conditions in Eastern Canada, and to investigate the interrelationships between protein and oil concentrations, seed weight and yield. A field experiment, including the high protein line OT89-16 and its recurrent backcross parent Maple Arrow grown side by side, was conducted at McGill University, during 1990 and 1991. The protein concentration of OT89-16 was 17 % greater than that of Maple Arrow for both years. However, the protein yield of OT89-16 was not significantly increased, the oil content was 19 to 23 % lower, and oil yield per ha was over 30 % lower than those of Maple Arrow. The lower yield of OT89-16 was closely associated with its lighter seeds. Further efforts to improve the high protein line should attempt to maintain the same high protein levels but achieve yield equal to that of the parent line through selection for heavier seeds.     

粗毛型长毛兔生长发育及产毛量的研究

对选育出的牛泉粗毛型长毛兔１００只种兔的生长发育及产毛量进行了研究。结果表明：Ｗ以母兔的初生个体重分别为５６．５３克和５６．６７克，成年公母兔体重分别为４４０３．３５克和４４４６．６５克，成年公母兔年剪毛量分别为１２３３．５０克和１２４９．４３克。体尺、体重、单次剪毛量间均呈极显著的正相关（Ｐ＜０．０１）。直接影响单次剪毛量最大的性状是体重，其相关和通径系数较高（ｒｙｘ５＝０．９６３０，ｐｙｘ５＝０．９２３３）。     

Irregular Sampling Theorem on the Frame

From the space V 0 , the scaling function of it is found. It is possible to transform the frame of V 0 into Riesz base of it (of course, the orthogonal bases are also Riesz bases),so that the irregular sampling theorem on the frame is changed into the one on the Riesz bases, in other words, the irregular sampling theorem on the Riesz bases is extend onto the frame. The irregular theorem on the frame can be used to the signal process.     

Research Progress and Breeding Prospects of Grain Size Associated Genes in Rice

The breeding objectives of rice include high yield and good quality. Grain size is the three-dimensional structure of seeds, which is one of the key traits determining grain yield and quality in rice. To date, more than 60 genes associated with grain size have been cloned, but the application of grain size genes in rice breeding has not been summarized. This review covers the current advances which can deepen our understanding, such as the key genes for grain size, genetic mechanism behind this trait, breeding application of cloned genes, functional markers for molecular breeding and prospects for future study, which will provide information of molecular breeding for rice breeders.     

Comparison of spatiotemporal patterns in reproduction of the kuruma prawn Marsupenaeus japonicus between two regions having different geographic conditions in Kyushu, southern Japan

ABSTRACT:   The Yatsushiro Sea and Shibushi Bay are, respectively, located on the western and south-eastern coast of Kyushu, southern Japan. The Yatsushiro Sea is a shallow semi-enclosed inland sea, whereas Shibushi Bay is an open-type bay with a deep and wide mouth facing the open sea. The size at sexual maturity and spatiotemporal patterns of reproduction of the kuruma prawn Marsupenaeus japonicus (Decapoda, Penaeidae) were examined and compared between these two regions. In the Yatsushiro Sea, the size at sexual maturity was estimated to be 131 mm body length. However, the estimated size at sexual maturity was considerably larger (154 mm) in Shibushi Bay. The spawning season of M. japonicus was estimated to continue from April to September in the Yatsushiro Sea, whereas it was estimated to be longer in Shibushi Bay, from March to November. It is believed that the warm water temperature due to the strong effect of the Kuroshio Current prolonged the spawning season of M. japonicus in Shibushi Bay. The spawning grounds were estimated to be in areas deeper than 10 m in the Yatsushiro Sea and deeper than 20 m in Shibushi Bay. In Shibushi Bay, body size distribution of mature females was considered to be less affected by water depth in comparison with the Yatsushiro Sea, although older mature females larger than 200 mm body length also spawned outside of the bay.     

Effects of forage source and particle size on chewing activity,ruminal pH,and saliva secretion in lactating Holstein cows

The present study investigated the effects of dietary forage source (quality) and particle size on chewing activity, saliva secretion, and ruminal pH. Twelve multiparous lactating Holstein cows, four of which were ruminally cannulated, were used in a replicated 4 × 4 Latin square experimental design with a 2 × 2 factorial arrangement of treatments. Cows fed wild‐rye hay diets had longer daily eating times than cows fed oaten hay diets. Treatments had no effect on ruminating time; therefore, resting time varied inversely to eating time. Neither the rate nor the amount of saliva secretion while eating, ruminating, or resting was affected by diet, resulting in similar total daily saliva secretions across treatments (231 L/day). Total volatile fatty acids (VFAs) in the ruminal fluid from animals fed oaten hay diets were higher than those from animals fed wild‐rye hay diets; further, VFAs increased with decreasing forage particle size (FPS). Consistent with elevated VFA concentrations, reducing FPS and including oaten hay in the diet decreased mean ruminal pH and increased the daily time of ruminal pH under 5.8. Results of this study suggest that forage source and particle size affect ruminal pH might be via variations in VFA production rather than increased salivary recycling of buffering substrates.     

Genetic relationship of litter traits between farrowing and weaning in Landrace and Large White pigs

We estimated genetic parameters in Landrace and Large White pig populations for litter traits at farrowing (total number born, number born alive, number stillborn, total litter weight at birth (LWB), and mean litter weight at birth) and those at weaning (litter size at weaning (LSW), total litter weight at weaning (LWW), mean litter weight at weaning (MWW), and survival rate from farrowing to weaning). We analyzed 65,579 records at farrowing and 6,306 at weaning for Landrace, and 52,557 and 5,360, respectively, for Large White. Single‐trait and two‐trait repeatability animal models were exploited to estimate heritability and genetic correlation respectively. Heritability estimates of LSW were 0.09 for Landrace and 0.08 for Large White. Genetic correlations of LSW with MWW were –0.43 for Landrace and –0.24 for Large White. Genetic correlations of LSW with LWW and LWB ranged from 0.5 to 0.6. The genetic correlation of MWW with LWW was positive, but that with LWB was negligible. The results indicate that utilizing LWW or LWB could improve LSW efficiently, despite the antagonistic genetic correlation between LSW and MWW.