排序方式： 共有37条查询结果，搜索用时 15 毫秒
31.
Live shelterbelts are common elements in coastal land areas and play an important role in reducing wind speed and sand drift. A simple measured index, that well represents relationship between shelterbelt structure and wind speed reduction, is required by landowners to enable them in establishing more effective shelterbelts. A three-dimensional crown (3D) density is proposed, which can be easily identified through shelterbelt parameters including maximum height, shelterbelt width, vertical crown/stem area ratio, and horizontal crown/stem area ratio. The utility of the index was tested in 10-year-old Casuarina equisetifolia and in 7-year-old Acacia auriculiformis shelterbelts in north central Coast of Vietnam. There was a significant negative linear relationship (R 2 = 0.64, p < 0.001) between 3D density and wind speed reduction efficiency, while there was no relationship between a two-dimensional crown density and wind speed reduction efficiency. Reduction efficiency was found to increase at higher wind speeds in shelterbelts of A. auriculiformis, but not C. equisetifolia. The A. auriculiformis shelterbelt was more efficient in reducing wind speed compared to C. equisetifolia shelterbelt. The former recovered 70 % wind speed at 130 m (16.5H) leeward, while it recovered 70 % at 85 m (8H) leeward in C. equisetifolia shelterbelt. 相似文献
32.
33.
Hidetoshi Minamiyama Masafumi Shimizu Hitoshi Kunoh Tamotsu Furumai Yasuhiro Igarashi Hiroyasu Onaka Ryuji Yoshida 《Journal of General Plant Pathology》2003,69(1):65-70
An endophytic actinomycete, isolate R-5 of Streptomyces galbus Frommer, that has promising potential as a biocontrol agent was originally isolated from field-grown rhododendron. In this
study, the mode of entry of R-5 into leaves of tissue-cultured seedlings of rhododendron was investigated in connection with
its production of cell wall-degrading enzymes. Light and scanning electron microscopy (SEM) revealed that R-5 grew on leaf
surfaces and entered leaf tissues via stomata and that the internal mycelia grew out of stomata after colonization in host
tissues. Micromanipulation at the SEM level demonstrated a prominent depression in the host surface at the interfaces with
the mycelia, suggesting that such a depression could be caused by degradation of cell wall components by hydrolytic enzymes
secreted from R-5 mycelia. In subsequent plate assays, R-5 produced cellulase, pectinase, xylanase, and nonspecific esterase
when cultured in liquid medium. Moreover, R-5 multiplied in mineral medium containing cellulose, pectin, or xylan as a single
carbon source. Thus, R-5 mycelia could degrade host cell walls at contact sites and probably utilize the degradation products
as carbon sources.
Received: May 16, 2002 / Accepted: July 9, 2002 相似文献
34.
Tamotsu Sato 《Journal of Forest Research》2010,15(6):404-410
This study quantified the mass and inputs of coarse woody debris (CWD) in two old-growth lucidophyllous forests in southwestern
Japan: in a steep slope area at Aya and in a flattish bottomland at Okuchi. CWD mass averaged 36.85 Mg ha−1 with eightfold variations at Aya, and 20.77 Mg ha−1 with more than 40-fold variations at Okuchi. CWD inputs estimated from long-term data on tree mortality averaged 36.76 Mg ha−1 over 16 years at Aya and 44.11 Mg ha−1 over 11 years at Okuchi. In both plots, fallen logs were the major form of CWD mass: 74.4% at Aya and 60.2% at Okuchi. About
19% of CWD was snapped and 7% was uprooted at Aya, and about 34% was snapped and 5.4% was uprooted at Okuchi. The CWD mass
differed markedly with topographic conditions in both plots, increasing from valleys up to ridges at Aya and from forest down
to a stream at Okuchi. Canopy gaps enhanced CWD mass and inputs in both plots: CWD input under gaps was two to three times
that beneath closed canopy. These results imply that typhoons would increase CWD mass and inputs on upper slopes on account
of the high aboveground biomass stocks and existence of large-diameter trees. 相似文献
35.
36.
Evelyn Aigho?Aremu Tamotsu?Furumai Yasuhiro?Igarashi Yukio?Sato Hajime?Akamatsu Motoichiro?Kodama Hiroshi?OtaniEmail author 《Journal of General Plant Pathology》2003,69(4):211-217
Fistupyrone (FP), a metabolite from Streptomyces sp. TP-A0569, inhibited the in vivo infection of Chinese cabbage seedlings by Alternaria brassicicola. To detect the possible action sites of FP, the effect of FP on the infection behavior of A. brassicicola and A. alternata was investigated. When spores of A. brassicicola were suspended in FP solution and inoculated on host leaves, FP at 0.1ppm significantly inhibited spore germination, appressorial formation, and infection hypha formation of A. brassicicola. Host-specific AB-toxin production and lesion formation by A. brassicicola spores were also reduced significantly by treatment with FP 1ppm. The effect of FP seemed to be irreversible because significant washing of FP-treated spores with distilled water (DW) did not change the inhibitory effects. In contrast, A. alternata isolates such as Japanese pear pathotype, apple pathotype, and saprophyte behaved almost equally in both FP- and DW-treated spores. Mycelial dry weight in potato dextrose broth and mycelial diameters on potato dextrose agar, gelatin glucose agar, and Czapek solution agar of both A. brassicicola and A. alternata were not different with or without addition of FP. These results indicate that FP at low concentrations has a fungicidal effect on spores of A. brassicicola but not on spores of A. alternata; FP also does not affect the vegetative phase of these fungi. 相似文献
37.
David M. Olszyk Tamotsu Shiroyama Jeffrey M. Novak Mark G. Johnson 《Communications in Soil Science and Plant Analysis》2018,49(16):2025-2041
We developed a rapid-test to screen for effects of biochar on seed germination and soils. Crop seeds were placed in containers and covered with 15 g of soil with 1% biochar by weight. Two agricultural soils from South Carolina USA were used. Eighteen biochars were produced from six primary feedstocks [pine chips (PC), poultry litter (PL), swine solids (SS), switchgrass (SG); and two blends of PC and PL, 50% PC/50% PL (55), and 80% PC/20% PL (82)]. Each feedstock was pyrolyzed at 350, 500 and 700°C. There were few biochar effects on seed germination. Shoot dry weight was increased for carrot, cucumber, lettuce, oat, and tomato; primarily with biochars containing PL. Soil pH, electrical conductivity and extractable phosphorus primarily increased with PL, SS, 55, and 82 treatments for both soil types and across species. This method can be an early indicator of biochar effects on seed germination and soil health. 相似文献