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31.
Symptoms of fairy rings caused by Lepista sordida have been reported on Zoysiagrass (Zoysia spp.) turf maintained at fairway height (2 cm), but not on bentgrass (Agrostis spp.) maintained at putting green height (0.5 cm). The mycelia of this fungus inhabit primarily the upper 0–2 cm layer of
the soil extending into the thatch. To compare conditions for the mycelial growth in Z. matrella turf to those in A. palustris turf, we examined the effects of nutrients, temperature, water potential, and pH in the field as well as in the laboratory.
Greater growth of the mycelia was observed in medium that included hot water extracts from soil of the 0–1 cm zone in Z. matrella turf compared to that from A. palustris. The upper soil layer in Z. matrella turf contained more organic matter from clippings than that in A. palustris. The temperature and water potential of the 0–2 cm soil zone in Z. matrella turf were also more favorable for the mycelial growth. The soil pH values of this zone in Z. matrella turf were less favorable compared to A. palustris but within the range for accelerating mycelial growth.
Part of this study was presented orally at the 46th meeting of the Mycological Society of Japan in 2002 相似文献
32.
Back-calculation usually requires measurements of growth marks revealed on otoliths by specific preparations. The standardization of the grinding (or sectioning) plane is necessary, but difficult, especially along the antero-posterior axis. In order to show the importance of the grinding plane, tetracycline labelling of eel otoliths ( Anguilla anguilla L.) has been used. This marking has a calcio-traumatic effect on otoliths, which can be revealed with staining techniques. Unless the grinding plane is incorrect, the tetracycline labelling and the staining of the ground surface are then superposed. 相似文献
33.
Estimates of age derived from daily ring counts from otoliths and capture rates of larval June sucker Chasmistes liorus were used to determine the relationship between discharge rates of the Provo River and residence time and patterns of larval drift. During 1997, larval drift occurred over a 22 day period when discharge rates were low (mean ±s.d. 3·2 ± 0·0 m3 s?1). In 1998, larval drift occurred in two separate events over a 40 day period. Discharge was higher during the first larval drift period (19 days; 24·8 ± 1·3 m3 s?1) and lower during the second larval drift period (17 days; 7·0 ± 0·9 m3 s?1). In 1997, no larval fish were collected at the lowermost transect on the Provo River (nearest Utah Lake), and few larvae >21 days of age were found. During the first drift period of 1998, larval C. liorus were collected at all transects, and mean age of larvae collected between upstream and downstream transects increased by c. 7 days. During the second drift period of 1998, only a few were collected in the lowermost transects, and age did not increase with proximity to the lake. Patterns in catch and age distribution of larval C. liorus in the lower Provo River suggest that recruitment failure occurs during the larval drift period in years with insufficient discharge to transport larvae into the lake. 相似文献
34.
35.
Two crystalline forms of (dithiodiphenylphosphinate)(phenyl)(triphenylphosphine)-palladium(II) (C36H30P2PdS2), one without solvent, the other containing THF (C4H8O), are obtained after reaction of sodium diphenyldithiophosphinate with (phenyl) (bis-triphenylphosphine) palladium(II) chloride and crystallisation from two different solvent mixtures. The molecular structures, as determined by single crystal X-ray diffraction, differ in the planarity of the 4-membered palladium dithiophosphinate rings. The experimental conformations have been compared to the conformations of four-membered metal-S2P rings reported in the Cambridge Structural Database. A flat conformation is more common than a puckered one. DFT calculations at the B3LYP level of theory indicate that the flat conformation of a model metallodithiophosphinate ring is very slightly lower in energy (1.2 kcal/mol) than the puckered conformation. 相似文献
36.
目的:探讨有氧运动对大鼠胸主动脉内皮依赖性舒张功能影响的机制。方法:12只SD大鼠随机分为有氧运动和对照两组(n=6),经过8周每天1 h的游泳训练后(每周5天),测定比较2组间大鼠胸主动脉舒张功能的改变。结果:有氧运动组一氧化氮(NO)和前列环素PGI2途径胸主动脉舒张功能的Rmax值较对照组明显提高(P<0.05)。结论:有氧运动对大鼠胸主动脉舒张功能的有益影响,主要是由NO和PGI2途径介导的。 相似文献
37.
38.
B. Pintos M. A. Bueno B. Cuenca J. A. Manzanera 《Plant Cell, Tissue and Organ Culture》2008,95(2):217-225
Cork oak (Quercus suber) somatic embryos were coated with alginate for the production of synthetic seeds and their storability for commercialization
was investigated. Also, the automatic monitoring of somatic embryo growth with a digital system of image capture was tested.
A power regression model was fitted between size and fresh weight (Adjusted R-squared = 0.96). This method permitted growth
assessment without contamination risk and opens the possibility of an automated control of culture growth for the future up
scaling of plant production. Conversion rate of synthetic seeds was higher on medium supplemented with mineral nutrients than
on medium without nutrients. Also, when the somatic embryos were coated without mineral nutrients added to the capsule, conversion
rate was significantly lower. The addition of sucrose to the capsule had no significant effect on the conversion rate. No
differences were recorded between 50 and 100 mM CaCl2 for capsule complexation. Synthetic seeds were cold stored at 4°C for two months without significant loss of conversion capacity.
The present study reports the first attempts to determine optimal storage time and conditions for conversion of encapsulated
somatic embryos of cork oak. 相似文献
39.
Adrian Ares Constance A. Harrington Thomas A. Terry Joseph M. Kraft 《Trees - Structure and Function》2008,22(5):603-609
The stable carbon (C) composition of tree rings expressed as δ13C, is a measure of intrinsic water-use efficiency and can indicate the occurrence of past water shortages for tree growth.
We examined δ13C in 3- to 5-year-old rings of Douglas-fir (Pseudotsuga menziesii (Mirb) Franco) trees to elucidate if decreased water supply or uptake was a critical factor in the observed growth reduction
of trees competing with understory herb and shrub vegetation compared to those growing without competition. We hypothesized
that there would be no differences in δ13C of earlywood in trees growing in plots with competing vegetation and those in plots receiving complete vegetation control
during 5 years because earlywood formed early in the growing season when soil water was ample. We also hypothesized that δ13C in latewood which was formed during the later half of the growing season when precipitation was low, would be greater (less
negative) in trees in plots without vegetation control. We then separated early and latewood from rings for three consecutive
years and analyzed their δ13C composition. No significant differences in earlywood δ13C in years 3–5 were observed for trees in the two vegetation control treatments. δ13C of untreated latewood separated from wood cores was greater in 4- and 5-year-old rings of trees growing with competing vegetation
compared to trees growing without vegetation competition (i.e., −25.5 vs. −26.3‰ for year 4, and −26.1 vs. −26.8‰ for year
5). Results suggest that water shortages occurred in Douglas-fir trees on this coastal Washington site in the latewood-forming
portion of the growing season of years 4 and 5 in the no-vegetation control treatment. We also compared δ13C from untreated wood, crude cellulose extracted with the Diglyme–HCl method, and holocellulose extracted with toluene–ethanol
to see if the extraction method would increase the sensitivity of the analysis. δ13C values from the two extraction methods were highly correlated with those from untreated samples (r
2 = 0.97, 0.98, respectively). Therefore, using untreated wood would be as effective as using crude cellulose or holocellulose
to investigate δ13C patterns in young Douglas-fir. 相似文献
40.
New copper(II) complexes [CuL2]2+ (L2=7,7,9-trimethyl-1,3,6,10,13-pentaazabicyclo[11,2,11.13]hexadec-9-ene) and [Cu2(L3)(H2O)2]4+ have been prepared by the reaction of [CuL1]2+ (L1=5,5,7-trimethyl-1,4,8,11,14-pentaazatetradce-7-ene) and formaldehyde. The mononuclear complex [CuL2]2+ has a square-planar coordination geometry with a 5-6-5-6 chelate ring sequence and is relatively stable even in low pH at room temperature. The dinuclear complex [Cu2(L3)(H2O)2]4+ consists of two unsaturated 15-membered pentaaza macrocyclic units (7,7,9-trimethyl-1,3,6,10,13-pentaazacyclopentadec-9-ene) that are linked together by a methylene group in a tilted face-to-face arrangement [Cu?Cu distance: 7.413(2) Å ]. Each macrocyclic unit of [Cu2(L3)(H2O)2]4+ contains one four-membered chelate ring and has a severely distorted octahedral coordination polyhedron. The dinuclear complex is quite stable in aqueous solutions containing an excess of formaldehyde or in dry acetonitrile but is decomposed to [CuL1]2+ and [CuL2]2+ in pure water. 相似文献