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991.
通过采用正交施肥设计在温室进行沙培试验,并作田间施肥试验,建立樟子松S_(1-1)苗木根干重、新梢干重和全干重与N、P的函数方程,并通过该方程求出适宜的施肥量:N为0.6g/ L,P为0.04g/L。 相似文献
992.
Brown fruit spot symptoms were observed on yellow Spanish melons ( Cucumis melo var. inodorus ) grown in greenhouses at Almeria in Spain. Nonsporing, motile, rod-shaped bacteria were isolated from diseased fruits, which on nutrient agar produced small yellow colonies. Two bacterial isolates, used for further investigations, were pathogenic on fruits but not on cotyledons of Spanish melon plants. They provoked disease symptoms similar to those observed in the greenhouse. Both isolates were Gram-negative, catalase-positive, weakly oxidase-positive and phenylalanine deaminase-negative. They hydrolysed esculin but not gelatin and they utilized glucose oxidatively. Fatty acid analysis revealed that both isolates belong to the genus Sphingomonas . In addition, 16S rDNA sequence analysis, performed on one isolate, demonstrated that it had a significant sequence similarity (more than 98%) with Sphingomonas pruni and Sphingomonas mali , nonphytopathogenic bacteria isolated from plants. Although enterobacterial repetitive intergenic consensus PCR and repetitive extragenic palindromic PCR seem to indicate that the Sphingomonas isolates from Spanish melon fruits may belong to a new species, DNA–DNA hydridization analysis is necessary to verify this hypothesis. 相似文献
993.
箭杆杨和梭梭柴水量平衡的研究 总被引:8,自引:3,他引:8
采用非称重蒸渗仪对箭杆杨、梭梭柴的水量平衡各分量变比规律进行了探讨.箭杆杨和梭梭柴水量平衡各分量的分配比例为:灌溉+降水均为100%,蒸散量51.1%、77.7%,渗漏量48.9%、14.2%,土壤水变化量不足0.1%、8.1%.分别就两个树种灌溉对蒸散和渗漏水分循环的影响进行了分析。初步确定二年生箭杆杨合理灌溉指标为:5、9两月每月灌溉1次,灌溉量900m3/ha(90mm),6、7、8三个月每月灌溉两次,每次的灌溉量也为90Om3/ha,每月为1800m3/ha。每公顷每年由造林规程的9900—13200m3/ha减少到7200m3/ha。梭梭柴保证每年11月初灌溉1次.灌溉量1500m3/ha(150mm)。 相似文献
994.
Consumption of pea (Pisum sativum L.) protein-treated wheat flour by the red flour beetleTribolium castaneum (Herbst.), the rice weevilSitophilus oryzae (L.) and the lesser grain borerRhyzopertha dominica (F.), was significantly reduced compared with wheat flour alone. Consumption was affected when the insects were exposed for
3 days to flour disks containing protein-rich fraction of the ‘Bonneville’ pea variety. Antifeedants present in the pea protein
fraction are apparently responsible for the reduced feeding response in these species.
http://www.phytoparasitica.org posting May 6, 2004. 相似文献
995.
Koji Tanina Motoaki Tojo Hirotaka Date Hideo Nasu Shinji Kasuyama 《Journal of General Plant Pathology》2004,70(3):188-191
Severe rot was found at the base of leaves and stems of chingensai (Brassica campestris L. chinensis group) in Okayama Prefecture in 2000. The causal fungi were morphologically identified as Pythium ultimum Trow var. ultimum and P. aphanidermatum (Edson) Fitzpatrick. This is the first report of rot caused by Pythium species on chingensai. We named this disease Pythium rot of chingensai. 相似文献
996.
Tania Schoennagel Monica G. Turner Daniel M. Kashian Andrew Fall 《Landscape Ecology》2006,21(8):1281-1296
A probabilistic spatial model was created based on empirical data to examine the influence of different fire regimes on stand
structure of lodgepole pine (Pinus contorta var. latifolia) forests across a >500,000-ha landscape in Yellowstone National Park, Wyoming, USA. We asked how variation in the frequency
of large fire events affects (1) the mean and annual variability of age and tree density (defined by postfire sapling density
and subsequent stand density) of lodgepole pine stands and (2) the spatial pattern of stand age and density across the landscape.
The model incorporates spatial and temporal variation in fire and serotiny in predicting postfire sapling densities of lodgepole
pine. Empirical self-thinning and in-filling curves alter initital postfire sapling densities over decades to centuries. In
response to a six-fold increase in the probability of large fires (0.003 to 0.018 year−1), mean stand age declined from 291 to 121 years. Mean stand density did not increase appreciably at high elevations (1,029
to 1,249 stems ha−1) where serotiny was low and postfire sapling density was relatively low (1,252 to 2,203 stems ha−1). At low elevations, where prefire serotiny and postfire lodgepole pine density are high, mean stand densities increased
from 2,807 to 7,664 stems ha−1. Spatially, the patterns of stand age became more simplified across the landscape, yet patterns of stand density became more
complex. In response to more frequent stand replacing fires, very high annual variability in postfire sapling density is expected,
with higher means and greater variation in stand density across lodgepole pine landscapes, especially in the few decades following
large fires. 相似文献
997.
998.
IntroductionChangbaipli1e(Pbllissylvestrisvar.sJIvesII.doIwlis)whicl1isararetreespeciesisendel11icil1Cl1al1gbaiMouIltaiI].TheareaofitSnaturaldistributiollisveryllinited,olllyabout2o()hm2onnortl1erl1sl()pcofCha11gbaiMoulltaill.However,Changbaipli1easal1il1lportanttrcesPecieshasmanyexcellentllatures,sllcl1asfastgrowing,straigl1ttrunk,goodwoodandsool1.Itiscalled"BeautyPli1e".Since196o's,lnanyCl1angbaipinepla11tatio11sllavebee1]planted.WeconductedstudicsOIlstructurealltIfl111ctiol1sofore… 相似文献
999.
红菜薹自交不亲和性快速测定初报 总被引:1,自引:0,他引:1
红菜薹的自交不亲和性表现为柱头抑制。授粉后24h的柱头,在电镜和荧光镜下观察,即可对其不亲和性进行测定。有些单株老龄花亲和性比幼龄花亲和性稍高。亲本亲和指数同后代条和指数的平均值呈正相关,因此在选择时,最好选择那些亲和指数低,不亲和性强的单株。 相似文献
1000.
R.P. Baayen M.G. Förch C. Waalwijk P.J.M. Bonants H.J.M. Löffler E.J.A. Roebroeck 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(9):887-894
Isolates of Fusarium oxysporum from lily were screened for pathogenicity, vegetative compatibility and DNA restriction fragment length polymorphisms, and compared to reference isolates of F. oxysporum f.sp. gladioli and F. oxysporum f.sp. tulipae to justify the distinction of F. oxysporum f.sp. lilii. Twenty-four isolates from different locations in The Netherlands (18 isolates), Italy (4 isolates), Poland and the United States (1 isolate each) shared unique RFLP patterns with probes D4 and pFOM7, while hybridization did not occur with a third probe (F9). Except for a self-incompatible isolate, these 24 isolates all belonged to a single vegetative compatibility group (VCG 0190). Isolates belonging to VCG 0190 were highly pathogenic to lily, but not to gladiolus or tulip, except for a single nonpathogenic isolate. Six saprophytic isolates of F. oxysporum from lily were nonpathogenic or only slightly aggressive to lily, gladiolus and tulip, belonged to unique VCGs and had distinct RFLP patterns. Three pathogenic isolates previously considered to belong to F. oxysporum f.sp. lilii were identified as F. proliferatum var. minus; all three belonged to the same VCG and shared unique RFLP patterns. These three isolates were moderately pathogenic to lily and nonpathogenic to gladiolus and tulip. The reference isolates of F. oxysporum f.sp. tulipae were pathogenic to tulip, but not to lily and gladiolus; they shared a distinct RFLP pattern, different from those encountered among pathogenic and saprophytic isolates from lily, and formed a separate new VCG (VCG 0230). Reference isolates of F. oxysporum f.sp. gladioli belonging to VCG 0340 proved pathogenic to both gladiolus and lily, but not to tulip. These isolates, as well as isolates belonging to VCGs 0341, 0342 and 0343 of F. oxysporum f.sp. gladioli, had RFLP patterns different from those encountered among the isolates from lily or tulip. These findings identify F. oxysporum f.sp. lilii as a single clonal lineage, distinct from F. oxysporum f.sp. gladioli and f.sp. tulipae. 相似文献