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41.
Kanae Ishimaru Naoko Tokuchi Naoya Osawa Koji Kawamura Hiroshi Takeda 《Journal of Forest Research》2005,10(1):27-34
Information on primary growth behavior after planting is required for mixed-plantation revegetation using broad-leaved species. To estimate primary growth, especially from the perspective of crown coverage and changing growth rates, we examined the growth and survival of four broad-leaved species that are frequently used in erosion-control plantations in Japan. The species studied were Myrica rubra Sieb. et Zucc., Alnus pendula Matsum., Quercus glauca Thunb., and Q. serrata Thunb. The survival, height, and basal diameter of planted trees were measured over a 4-year period, and crown area was calculated over a 3-year period. We found a negative relationship between relative growth rate (RGR) and survival rate, suggesting that fast growth may be fatal when resources are severely limited. The relative height growth rate (RHGR) of A. pendula was especially high during the early period of the study (1997–1999) and then drastically declined, whereas the opposite tendency was observed in Q. glauca. The results of stem allometry analyses conformed to the specific relationships between height growth and diameter growth of the four species; increases in stem thickness based on height increments were smaller in the pioneer species A. pendula. Between-species differences in coverage per planted tree (mean crown area multiplied by survival rate) were small as a result of the negative relationship between coverage area and survival rate. 相似文献
42.
Paddy fields converted into winter wheat fields in Hokkaido, Japan, receive extremely high snowfall, creating a risk of flood damage to crops in spring due to waterlogging of snowmelt runoff and poor drainage. Meanwhile, in June there is relatively little rainfall, and a lack of moisture inhibits winter wheat growth. Therefore, we developed a method involving a series of 30-cm-deep ditches in agricultural fields to be used for drainage during the flood-prone period and for furrow irrigation during the dry period using water drawn from the canals that feed the paddy fields. The ditches are called ‘hybrid ditches’ as they are able to perform both drainage and irrigation functions. In this study, we investigated the optimal construction timing and spacing for hybrid ditches. We also evaluated their ability to improve the drainage and irrigation of winter wheat. We found that the optimal timing for digging hybrid ditches is immediately after sowing, and the inter-ditch spacing for irrigation should be 15 m or less. The hybrid ditches promoted increased soil temperature and healthy development of wheat plants by improving drainage during the flood-prone period. In addition, water was successfully supplied via the hybrid ditches to irrigate the fields in June. Under experimental conditions in which rainfall was excluded, grain yield was 10% higher and percent protein content was more than 1% point greater in the irrigated plot compared with the non-irrigated plot. Grain yield was also observed to increase by 3–29% in demonstration tests conducted at local farms. From these results, we conclude that hybrid ditches are capable of improving the growth and yield of winter wheat by improving drainage and providing irrigation in converted paddy fields in Hokkaido. 相似文献
43.
Kitoh K Katoh H Kitagawa H Nagase M Sasaki N Sasaki Y 《American journal of veterinary research》2001,62(5):770-774
OBJECTIVE: To determine whether heartworm (HW) extract-induced shock in dogs is consistent with anaphylactic shock by examining the role of histamine. ANIMALS: 6 mixed-breed dogs (3 without and 3 with HW infections) and 4 specific pathogen-free (SPF) Beagles. PROCEDURE: Four experiments were performed as follows: 1) 6 mixed-breed dogs were treated IV with 2 ml of HW extract, and plasma histamine concentrations were determined; 2) 4 SPF dogs were treated IV with 2 ml of HW extract and examined for shock; 3) sera from 6 dogs of experiment 1 and from 4 SPF dogs of experiment 2 that were obtained before HW extract treatment were tested for heterologous passive cutaneous anaphylaxis (PCA), using rabbits during a sensitization period of 48 to 72 hours; and 4) mast cell degranulation by HW extract was tested, using rat mesentery and canine cultured mast cells. RESULTS: Experiment 1: 6 dogs developed shock, and plasma histamine concentrations increased significantly from 0.3 +/- 0.2 (mean +/- SD) ng/ml before HW extract treatment to 44.6 +/- 68.9 ng/ml at the onset of shock; experiment 2: all SPF dogs developed shock and had an increase in plasma histamine concentrations; experiment 3: sera from mixed-breed dogs without HW infection and from SPF dogs had negative PCA reactions; experiment 4: HW extract degranulated rat mesentery mast cells and released histamine directly from canine mast cells. CONCLUSIONS AND CLINICAL RELEVANCE: Results of our study indicate that an unknown mast cell-degranulating substances contained in HW extract may degranulate mast cells directly, consequently releasing histamine that may participate in the onset of shock in HW extract-induced shock in dogs. 相似文献
44.
To control rice blast effectively at the nursery stage, the absolute SiO2 content necessary for rice plants to resist blast disease was investigated using various rice cultivars and soils. Nine rice cultivars with different complete resistance genes and different degrees of partial resistance were grown on nursery soils amended with silica gel at different rates to change the SiO2 content of rice plant. The rice seedlings were then inoculated 28 days after sowing with Pyricularia grisea to estimate their blast resistance. In all rice cultivars, the number of lesions was significantly reduced when SiO2 content increased in the rice seedling; lesions were reduced to 5%–20% of the number on the seedlings grown in soil without silica gel when the seedling SiO2 content reached 5%. Additionally, the susceptibility to blast disease of rice seedlings grown on eight soils collected from different districts, with varying amounts of silica gel, was compared. The number of lesions decreased significantly when the SiO2 content in the seedlings reached 5%. These results suggest that SiO2 content of at least 5% in the rice plant can control this disease at the nursery stage under any conditions. 相似文献
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49.
Nakano S Kishi H Ogawa H Yasue H Okano A Okuda K 《The Journal of reproduction and development》2003,49(2):127-134
We investigated endometrial expression of trophinin mRNA and protein, homophilic cell adhesion molecules, during the estrous cycle of gilts. An immunopositive reaction for trophinin was observed in the luminal and glandular epithelia of the endometrium at all stages of the estrous cycle, but not in endometrial stromal cells or the myometrium. A partial coding sequence of porcine trophinin was similar to sequences in humans and mice, with homologies of 75% and 70%, respectively. As in humans and mice, the trophinin gene is expressed in the endometrium. Trophinin, however, is expressed in the endometrium of the pig throughout the estrous cycle, higher expression levels were observed at some points of the luteal phase, as in humans. These findings suggest that regulation of trophinin gene expression in the pig is different from that in mice, but similar to that in humans. Furthermore, the present results suggest that the pig might be a suitable model for studying the physiological importance of trophinin in early pregnancy in humans. 相似文献
50.
Mohamed T Oikawa S Nakada K Kurosawa T Sawamukai Y Sato H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(7):821-824
A new method for catheterization of the portal and hepatic veins in cattle by means of the over-the-wire system was investigated to maintain more reliable long-term patency of catheters. Four cattle were used to evaluate the success rate, patency and safety of the procedure. The catheters, coated by urokinase were patent as long as they were in situ. In addition, the introducer was useful to prevent the catheter from being broken. No complications developed during the10 days after the procedure. Two cows were then euthanized. Post mortem findings were minimal. The results of the study reported here are promising, the benefits are significant and there is no apparent disadvantage to its use. 相似文献