樟子松苗木沙培试验施肥效应的研究

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。     

Brown spot caused by Sphingomonas sp. on yellow Spanish melon fruits in Spain*

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.     

Aggressiveness of Verticillium dahliae isolates from different vegetative compatibility groups to potato and tomato

Aggressiveness of Verticillium dahliae isolates from three vegetative compatibility groups (VCGs) was tested on potato and tomato. VCG4B was the most aggressive to potato and VCG2A was the most aggressive to tomato; VCG2B was the least aggressive to both potato and tomato. In potato, disease incidence, symptom severity and colonization index of stem segments were significantly higher in plants inoculated with VCG4B isolates than in those inoculated with VCG2B and VCG2A isolates. Inoculation with VCG4B and VCG2A decreased plant height and fresh weight more than inoculation with VCG2B. In tomato, VCG2A caused significantly more severe symptoms than either VCG4B or VCG2B. The colonization index in tomato plants inoculated with VCG2A was also significantly higher than in those inoculated with VCG4B and VCG2B. Similar patterns of relative aggressiveness were observed in potato and tomato when the pathogenicity of isolates of various VCGs, each originating from a specific host (cotton, potato or eggplant), was compared.     

箭杆杨和梭梭柴水量平衡的研究

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）。     

Reduced consumption of pea protein-treated flour disks by stored-product insects

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.     

Influence of fire regimes on lodgepole pine stand age and density across the Yellowstone National Park (USA) landscape

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.     

Structure and functions of Pinus sylvestris var. Sylvestriformis plantation ecosystem

IntroductionChangbaipli1e(Pbllissylvestrisvar.sJIvesII.doIwlis)whicl1isararetreespeciesisendel11icil1Cl1al1gbaiMouIltaiI].TheareaofitSnaturaldistributiollisveryllinited,olllyabout2o()hm2onnortl1erl1sl()pcofCha11gbaiMoulltaill.However,Changbaipli1easal1il1lportanttrcesPecieshasmanyexcellentllatures,sllcl1asfastgrowing,straigl1ttrunk,goodwoodandsool1.Itiscalled"BeautyPli1e".Since196o's,lnanyCl1angbaipinepla11tatio11sllavebee1]planted.WeconductedstudicsOIlstructurealltIfl111ctiol1sofore…     

红菜薹自交不亲和性快速测定初报

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。     

Pathogenic, Genetic and Molecular Characterisation of Fusarium oxysporum f.sp. lilii

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.     

樟子松人工林鼠害防治的探讨

根据樟子松人工鼠害发生特点和以往防治实践,提出了“以营林为基本措施”,生物,化学防治,人工和机械防除为辅助措施,综合防治樟子松鼠害”的方针,并着重阐述了营林防治措施及营造防鼠混交林的可行性和方法。