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91.
Breakdown and macroinvertebrate colonization of conifer needles (Cryptomeria japonica) and deciduous broadleaves (Euptelea polyandra) were investigated using litter bags in two study sites in streams flowing through a conifer plantation of C. japonica in Shikoku, southwestern Japan (one site with conifer canopy and another with mixed conifer and broadleaved canopy). Breakdown
rates and macroinvertebrate densities were compared between litter species (conifer needle vs broadleaf) and between the two
sites (conifer vs mixed canopy) to determine (1) whether breakdown rate of broadleaves is higher than conifer needles, (2)
whether macroinvertebrates prefer broadleaves to conifer needles, and (3) whether the difference in riparian canopy is reflected
in macroinvertebrate abundance. The results indicated that breakdown rates of broadleaves were higher than those of conifer
needles, suggesting poorer quality of the latter as food for macroinvertebrates. Differences in macroinvertebrate density
between needles and broadleaves were generally consistent with those in breakdown rates: broadleaves tended to have higher
densities than needles, suggesting that conifer needles were not preferred by macroinvertebrates. However, total macroinvertebrate
density in the conifer site was not significantly different from that in the mixed site, although the dominant shredder taxon
differed (conifer site: gammarids; mixed site: lepidostomatids). Although conifer needles are low-quality food for macroinvertebrates,
this may offer some advantages. Conifer needles remain on the streambed for longer periods owing to their lower breakdown
rates, being a constantly available resource. In addition, accumulations of conifer litter may effectively trap and retain
particulate organic matter. 相似文献
92.
93.
Reto M Figueira ME Filipe HM Almeida CM 《Plant foods for human nutrition (Dordrecht, Netherlands)》2007,62(4):139-144
To evaluate the potential benefits and risks associated with tea consumption it is important to identify the constituents
of this beverage. Levels of some minerals, caffeine and catechins in green tea samples commercialized in Portugal were evaluated.
Potassium is the metal present in larger amount (92–151 mg/l). The content of sodium, calcium, fluoride, aluminium, manganese
and iron were 35–69, 1.9–3.5, 0.80–2.0, 1.0–2.2, 0.52–1.9, 0.020–0.128 mg/l, respectively. Chromium and selenium were not
detected. The resulting data showed considerable variability in catechins content. The levels of epigallocatechin gallate
(EGCG) ranged from 117 to 442 mg/l, epicatechin 3-gallate (EGC) from 203 to 471 mg/l, epigallocatechin (ECG) from 16.9 to
150 mg/l, epicatechin (EC) from 25 to 81 mg/l and catechin (C) from 9.03 to 115 mg/l. Caffeine contents in the green tea infusions
studied were between 141–338 mg/l. Green tea infusions provide significant amounts of catechins and could be an important
source of some minerals. 相似文献
94.
Growth,P uptake and rhizosphere properties of wheat and canola genotypes in an alkaline soil with low P availability 总被引:1,自引:0,他引:1
Zakaria Solaiman Petra Marschner Dongmei Wang Zed Rengel 《Biology and Fertility of Soils》2007,44(1):143-153
The aim of the present study was to assess the role of soil type on growth, P uptake and rhizosphere properties of wheat and
canola genotypes in an alkaline soil with low P availability. Two wheat (Goldmark and Janz) and two canola genotypes (Drum
and Outback) were grown in a calcareous soil (pH 8.5) at two P levels [no P addition (0P) or addition of 200 mg kg−1 P as Ca3(PO4)2 (200P)] and harvested at flowering or maturity. Shoot and root dry weight, root length and shoot P content were greater in
the two canola genotypes than in wheat. There were no consistent differences in available P, microbial P and phosphatase activity
in the rhizosphere of the different genotypes. Shoot P content was significantly positively correlated with root length, pH
and phosphatase activity in the rhizosphere. The microbial community composition, assessed by fatty acid methylester analysis,
of the canola genotypes differed strongly from that of the wheat genotypes. The weight percentage bacterial fatty acids, the
bacteria/fungi (b/f) ratio and the diversity of fatty acids were greater in the rhizosphere of the canolas than in the rhizosphere of the wheat
genotypes. In contrast to the earlier studies in an acidic soil, only small differences in growth and P uptake between the
genotypes of one crop were detected in the alkaline soil used here. The results confirmed the importance of root length for
P uptake in soils with low P availability and suggest that the rhizosphere microbial community composition may play a role
in the better growth of the canola compared to the wheat genotypes. 相似文献
95.
Tetsuo Tamada 《Journal of General Plant Pathology》2007,73(1):76-80
Four lines (designated MR0, MR1, MR2, and M8) from 13 accessions of Beta vulgaris subsp. maritima were selected on the basis of phenotypes produced after foliar rub-inoculation with Beet necrotic yellow vein virus (BNYVV). The susceptible phenotype developed bright yellow local lesions, whereas the resistant phenotype had symptoms ranging
from no visible lesions to necrotic lesions at the inoculation site. MR1 and MR2 lines had a resistant phenotype depending
on the isolate and the MR0 line was susceptible to all isolates of BNYVV tested. The M8 line was highly susceptible; the virus
spread systemically and caused severe stunting. These plant lines will be useful for distinguishing BNYVV isolates having
different pathogenicities, especially those controlled by RNA3 and/or RNA5. 相似文献
96.
对15例百岁高龄老人进行了染包体畸变(CA)、淋巴细胞微核(MN)、姐妹染色单体互换(SCE)的观察。结果表明,年龄与自发频率呈正相关。 相似文献
97.
98.
为筛选防控甘蔗绵蚜和蓟马的理想缓释长效低毒新药剂及轻简高效施药技术,选用2%吡虫啉GR根施进行田间药效试验。田间试验结果表明:2%吡虫啉GR对甘蔗绵蚜和蓟马均具有良好的防控效果,是防控甘蔗绵蚜和蓟马理想的缓释长效低毒新药剂,与其它药剂轮换使用,可延缓抗药性产生和发展。2%吡虫啉GR最适宜用量为30 kg /hm2(有效成分600 g),可在2~6月结合甘蔗种植管理或大培土,按hm2用药量30 kg与hm2施肥量40~80 kg混匀一次性施用,对甘蔗绵蚜的防效可达98.2%以上,对甘蔗蓟马的防效可达81.1%以上;甘蔗实测产量较对照增加33390 kg/hm2以上,甘蔗糖分较对照增加6.6%以上。缓释长效强内吸性农药与底肥追肥混匀一次性根施,施用方便,轻简高效,省工省时,环境友好,应在蔗区大面积推广应用。 相似文献
99.
100.
Edak Aniedi Uyoh Ikootobong Sunday Urua Valentine Otang Ntui Elza Cletus Okpako 《Journal of Crop Science and Biotechnology》2011,14(4):227-232
Nuclear DNA of three accessions of Parkia biglobosa collected from three locations in northern Cross River State was investigated using a Patec PA II flow cytometer equipped
with an argon ion laser (488 nm), and pictures of mitotic chromosomes were taken using a digital micro-camera (Canon) placed
on the eye piece of a binocular microscope at 100X oil immersion. Metaphase chromosome counts of 2n = 22 for accessions A
and C and 2n = 24 for accession B, were obtained and through flow cytometry, the three accessions were confirmed to be diploids.
The nuclear DNA content and genome size for the accessions were 1.5085, 1.489, and 1.5266 pg (737.7054, 728.121, and 746.5074
Mbp) for accessions A, B, and C, respectively. In another experiment, leaf samples from greenhouse-germinated seeds were analyzed
for variation in the banding pattern of the protein by SDS-PAGE in the three accessions. Protein was resolved into three banding
groups according to their electrophoretic mobility: slow, medium, and fast, clustering between 100–200, 40–70, and 10–25 kDa,
respectively. There was 76% similarity in the banding pattern between the accessions. 相似文献