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Lago JH Soares MG Batista-Pereira LG Silva MF Corrêa AG Fernandes JB Vieira PC Roque NF 《Phytochemistry》2006,67(6):589-594
GC and GC-MS analyses of the volatile oils from Guarea macrophylla (Meliaceae) collected during three different periods in one year (February, June and October) indicated a seasonal variation in chemical composition. Whilst sesquiterpenes were the predominant class of components present in the leaf oil, a seasonal dependent variation in the degree of oxygenation of these compounds was detected, which seemed to be associated with phenological factors. The leaf oil, and fractions thereof, were subjected to GC coupled with electroantennographic detection employing antennae of females of Hypsipyla grandella, an insect pest that attacks several meliaceous species. Five compounds elicited significant responses and these were identified as ledol, 1-cubenol, guai-6-en-10beta-ol, 1-epi-cubenol, and tau-muurolol. The results suggest that these components could be responsible for the attraction of H. grandella to G. macrophylla. 相似文献
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敌百虫对水丝蚓的毒害 总被引:14,自引:0,他引:14
采用急性毒性方法测定了被不同浓度敌百虫毒害的水丝蚓(Limnodilus hoffineisteri)半致死浓度(LC50),利用测定酶活性方法检测了水丝蚓超氧化物歧化酶(SOD)的变化及中毒后水丝蚓喂饲的强壮水螅(Hydra robusta)SOD的改变。(1)敌百虫对水丝蚓48 h LC50为3.29 mg/L。敌百虫对水丝蚓SOD活性影响显著(P<0.05):在低浓度1~4 mg/L时,SOD活性呈上升趋势,但随浓度增加至5 mg/L,SOD活性开始下降。(2)用1~8 mg/L中毒后的水丝蚓依次喂饲水螅,SOD活性呈上升趋势。实验结果表明,敌百虫作为重要的杀虫剂或作为防治鱼病的药物,对水丝蚓造成胁迫,并在一定浓度范围内直接或间接地影响以其为食的动物的生存,以至危害生命。 相似文献
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Abstract Data are reported showing large directional changes in the frequencies of some gene arrangements and arrangement combinations in certain natural populations of Drosophila robusta in the eastern United States. The changes involve the same X‐chromosomal inversion differences in two of the three localities studied and similar autosomal inversions in all three. These genetic changes provide a rare opportunity to observe evolutionary forces at work in nature. They are interpreted as being due to natural selection. 相似文献
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Cluster root development in Grevillea robusta (Proteaceae). I. Xylem, pericycle, cortex, and epidermis development in a determinate root 总被引:1,自引:0,他引:1
The cluster roots of Grevillea robusta A. Cunn. ex R. Br. are composed of determinate rootlets that stop growing, but remain physiologically active for several months. Their apical organization, both before and after maturation, was studied by light and transmission electron microscopy. Each cell layer forms a dome, with an initial cell at its end. Xylem elements form a complicated triarch array at the base of the rootlet, passing along the rootlet as two files, and then joining at the tip to form a single file, surrounded by six pericycle cells. At the base of the rootlet, shorter xylem cells and thick-walled support cells are visible. A root cap, present in rootlets grown in vermiculite, was eventually displaced by root hair growth. Rootlets grown in Hoagland's solution lacked root caps and were significantly shorter than those grown in vermiculite. Cell fate was analysed in terms of cell position and is discussed in terms of pattern and development. 相似文献
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Sieve size effects on root length and biomass measurements of maize (Zea mays) and Grevillea robusta
The purpose of this study was to investigate the effects of different mesh sizes on the recovery of root length and biomass
and to determine whether the degree of recovery was influenced by plant species and sample location. Sieves of 2.0, 1.0, 0.5
and 0.25 mm (4.0, 1.0, 0.25 and 0.06 mm2) mesh sizes were used to recover and measure the root length and biomass of Zea mays
L. (maize) at 0–15 cm and 30–45 cm depths and of Grevillea robusta A. Cunn. ex R. Br. (grevillea) at the same depths 1.0 m
and 4.5 m from a line of grevillea trees. At 0–15 cm, the coarser sieves (sum collected with 2.0 and 1.0 mm sieves) recovered
approximately 80% of the total root biomass measured, but only 60% of the root length. The proportion of total maize root
length and biomass recovered by the coarser sieves decreased with soil depth. The proportion of total grevillea root length
recovered by the coarser sieves was similar at the two soil depths, but increased slightly with distance from the tree line.
The ≥ 0.5 mm sieves recovered between 93 and 96% of grevillea and maize root biomass and between 73 and 98% of their root
length, depending on the sample location. Roots passing through the 0.5 mm sieve, but recovered by the 0.25 mm sieve were
about 20% of total maize root length and grevillea root length at 1.0 m from the tree line but < 5% of the total grevillea
root length at 4.5 m from the tree. Roots passing through the 0.5 mm sieve but recovered by the 0.25 mm sieve contributed
only slightly to root biomass. Although the ≥ 0.5 mm sieves provided adequate measurements of root biomass, the ≥ 0.25 mm
sieves were required for accurate measurement of fine root length. There was no universal correction for root length and biomass
underestimation when large sieve sizes were used because the proportions of length and biomass recovered depended on the plant
species and on soil depth and distance from the plant.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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The Neodolichomitra robusta(Broth.)Nog.is a peculiar species in East Asia.Chromosome number of mitotic metaphase of stem tip cells in gametophyte is n=5.The karyotype,K(n)=5=4m十1sm,or K(n)=5=4v+1J,is 2A type.The result is reported for the first time. 相似文献
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