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51.
松墨天牛及其天敌花绒坚甲种群的三维空间分布格局 总被引:4,自引:2,他引:4
2003~2005年对纯林和混交林中的黑松、马尾松、湿地松诱木按1 m一个区段进行全株解剖,解剖的松墨天牛和花绒坚甲的资料用聚集强度的5种指数测定空间格局.两种林分3种松树上,松墨天牛和花绒坚甲水平分布的聚集强度指数均为扩散系数C>1,扩散指数Iδ>1,久野指数CA>0,丛生指数I>1,聚块性指数Iw>1,表明两者水平分布均为聚集格局,两者水平分布格局一致.垂直分布除混交林马尾松树上的花绒坚甲为聚集分布外,其余均为均匀分布,5种聚集强度指标均是C<1,Iδ<1,CA<0,Iw<1,I<0,花绒坚甲与松墨天牛三维空间分布格局一致,前者对后者在空间上有追随关系. 相似文献
52.
Rapid method of in vitro multiplication of date palm was developed. Shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with 2 mg dm–3 dimethylaminopurine (2iP) + 1 mg dm–3 naphthalene acetic acid (NAA). Shoot buds were proliferated from white nodular cultures on hormone free medium. Shoot bud proliferation strongly enhanced when cultured on MS-medium contained 3 mg dm–3 2iP + 0.5 mg dm–3 NAA. Culturing on full-strength MS medium showed higher multiplication rate compared with half-strength MS medium. Among four concentrations of sucrose used, 30 g dm–3 speeded up the bud proliferation more than 10, 20 and 40 g dm–3. However, the largest shoot buds were observed with 40 g dm–3 sucrose. Solidification of culture media by 1.75 g dm–3
Phytagel showed the highest proliferation rate, but the largest buds were observed with 1 g dm–3
Phytagel. 相似文献
53.
《Fungal Ecology》2019
Fusarium graminearum is the main causal agent of Fusarium head blight (FHB) of small grain cereals, but the importance of weeds in the FHB disease cycle and the establishment of F. graminearum in agroecosystems are still not fully understood. The objective of this study was to determine the potential role of weeds present within cereal crop rotations as alternative hosts. F. graminearum was isolated from different organs of asymptomatic weeds sampled from six fields with cereal-crop rotations in Lithuania for two consecutive years (2015 and 2016). The fungi were identified using morphological and molecular methods. Out of 57 weed species that were investigated, 41 (71.9%) harboured F. graminearum isolates. Twenty five weed species were identified as new, previously undocumented, hosts. The majority (73.3%) of the isolates of F. graminearum from this study belonged to the 15ADON genotype while a smaller proportion (23.4%) belonged to the 3ADON genotype. All F. graminearum isolates that were assessed induced FHB symptoms on artificially inoculated spring wheat tested in the field. 相似文献
54.
Young Woo Chun Richard B. Hall Loren C. Stephens 《Plant Cell, Tissue and Organ Culture》1986,5(3):179-185
The in vitro shoot proliferation of Populus alba × P. grandidentata was affected by the medium consistency and shoot density, but not by three sizes of vessels. After 4 weeks of culture, the fresh weight and number of shoots per explant on liquid medium were significantly greater than those on agar-solidified medium. In particular, 3.2 shoots, 7 mm or longer per explant, were produced on liquid medium compared with 1.6 shoots per explant or agar-solidified medium. The fresh weight per explant after 4 weeks of culture on liquid medium and agar-solidified medium were 0.68 and 0.25 g, respectively. Increasing the number of shoots per vessel slowed the growth of the explants as measured by fresh weight and the number of shoots produced. There was little difference in the number of shoots produced between vessels with 1 or 2 shoots per vessel, but there were many fewer shoots produced when 3 shoots were placed in each vessel.Journal Paper No. J-11977 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project 2210. 相似文献
55.
中国10种松树的疱锈病菌锈孢子表面形态,在扫描电镜下观察并进行比铰,可归纳为两种类型:一是以单维管束松类的五针松的红松疱锈病菌(Cronartium ribicola)为代表,包括华山松和西伯利亚红松;另一是以双维管束松类的云南松疱锈病菌(C. flaccidum)为代表,包括樟子松、油松、赤松、马尾松、黄山松、思茅松等。孢子表面突起的形状及环纹层次是识别这两种锈疱子的主要特征。 相似文献
56.
Photoautotrophic shoot and root development for triploid melon 总被引:2,自引:0,他引:2
Adelberg Jeffrey Fujiwara Kazuhiro Kirdmanee Chalermpol Kozai Toyoki 《Plant Cell, Tissue and Organ Culture》1999,57(2):95-104
The aim of this investigation was to establish environmental factors which promote growth and photosynthesis of melon (Cucumis
melo L.) shoot buds, in vitro, and determine if photoautotrophic shoots had superior root forming ability in photoautotrophic
environments. Buds from the triploid melon clone ‘(L-14×B)×L-14’ were observed for 21 days after transfer from a multiplication
MS medium with 3% sucrose and 10 μM benzyladenine (BA) to a shoot development medium with 1 μM BA at three levels of sucrose
in the medium (0, 1 and 3%), and light (50, 100 and 150 PPF) and CO2 (500, 1000 and 1500 ppm) in the culture chamber. More shoot buds were observed with 3% sucrose in the medium. Increased light
and CO2 had a positive interaction with shoot proliferation. Fresh and dry weights were greatest at 3% sucrose, 150 PPF light and
1500 ppm CO2. Shoot buds grew more slowly in sugar-free medium, but fresh and dry weight still doubled over 21 days of culture. Net photosynthetic
rates (NPR) of buds were negative after four days in treatment conditions, but became positive after transfer to fresh, sugar-free
medium. Two triploid genotypes of melon were (1) grown in vitro with sugar (photomixotrophic) and without sugar (photoautotrophic),
(2) rooted in sugar-free media, both in a laboratory controlled environment chamber (in vitro) and a greenhouse acclimatization
unit (ex vitro), and (3) compared for subsequent nursery growth in the greenhouse unit. The genotype ‘(L-14×B)×L-14’ produced
more shoots than ‘(L-14×B)×Mainstream’ in both photomixotrophic or photoautotrophic conditions. ‘(L-14×B)×L-14’ rooted as
well from either photoautotrophic and photomixotrophic shoots but ‘(L-14×B)×Mainstream’ rooted less frequently from photoautotrophic
shoots. Seventy-six percent of the shoots in the laboratory controlled environment chamber were able to root photoautotrophically,
whereas 47% of the shoots in the greenhouse acclimatization unit were rooted. Between 77% and 88% of plantlets from all treatment
combinations survived transfer to the nursery. After growth in the nursery, the sizes of plants (fresh weight, dry weight,
leaf area) were the same for either genotype, from either photoautotrophic or photomixotrophic shoots. Nursery plants that
had been rooted in the laboratory controlled environment chamber were larger than those rooted in the acclimatization greenhouse
chamber.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
57.
Impact of land‐use change to Jatropha bioenergy plantations on biomass and soil carbon stocks: a field study in Mali 下载免费PDF全文
Jeroen Degerickx Joana Almeida Pieter C.J. Moonen Leen Vervoort Bart Muys Wouter M.J. Achten 《Global Change Biology Bioenergy》2016,8(2):443-455
Small‐scale Jatropha cultivation and biodiesel production have the potential of contributing to local development, energy security, and greenhouse gas (GHG) mitigation. In recent years however, the GHG mitigation potential of biofuel crops is heavily disputed due to the occurrence of a carbon debt, caused by CO2 emissions from biomass and soil after land‐use change (LUC). Most published carbon footprint studies of Jatropha report modeled results based on a very limited database. In particular, little empirical data exist on the effects of Jatropha on biomass and soil C stocks. In this study, we used field data to quantify these C pools in three land uses in Mali, that is, Jatropha plantations, annual cropland, and fallow land, to estimate both the Jatropha C debt and its C sequestration potential. Four‐year‐old Jatropha plantations hold on average 2.3 Mg C ha?1 in their above‐ and belowground woody biomass, which is considerably lower compared to results from other regions. This can be explained by the adverse growing conditions and poor local management. No significant soil organic carbon (SOC) sequestration could be demonstrated after 4 years of cultivation. While the conversion of cropland to Jatropha does not entail significant C losses, the replacement of fallow land results in an average C debt of 34.7 Mg C ha?1, mainly caused by biomass removal (73%). Retaining native savannah woodland trees on the field during LUC and improved crop management focusing on SOC conservation can play an important role in reducing Jatropha's C debt. Although planting Jatropha on degraded, carbon‐poor cropland results in a limited C debt, the low biomass production, and seed yield attained on these lands reduce Jatropha's potential to sequester C and replace fossil fuels. Therefore, future research should mainly focus on increasing Jatropha's crop productivity in these degraded lands. 相似文献
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