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971.
Effects of Cadmium on Respiration Rate and Activities of Several Enzymes in Soybean Seedlings 总被引:4,自引:0,他引:4
K. C. LEE B. A. CUNNINGHAM G. M. PAULSEN G. H. LIANG R. B. MOORE 《Physiologia plantarum》1976,36(1):4-6
Soybean (Glycine max L. ev. Columbus) seedlings grown in culture solution were treated with cadmium as CdSO4. Final concentrations of cadmium (Cd2+) in the solution were 0, 0.45, 0.90, and 1.35 μM. Soybean leaves, analyzed 10 days after Cd2+ was added to the culture solution, showed increased respiration rate and activities of malate dehydrogenase, acid phosphatase, ribonuclease, deoxyribonuclease, and peroxidase but decreased activity of carbonic anhydrase. Increased activity of hydrolytic enzymes and peroxidase reflects a general senescence response while the carbonic anhydrase decrease is consistent with an antagonism between cadmium and endogenous zinc. Chlorosis, epinasty, abscission of leaves, and decreased growth rate occurred in seedlings treated with 1.35 μM Cd2+. 相似文献
972.
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975.
The meiotic inducing hormone, 1-methyladenine, first isolated from starfish has been implicated to play some role in the gamete maturation of a number of marine invertebrates. However, there have been controversial and sometimes opposite conclusions due to the fact that there is no direct bioassay system other than in starfish.
Using3 H-1-methyladenine, we demonstrated that the hormone was localized exclusively in the outer epithelial cells of gonads of sea urchins as revealed by autoradiography. Uptake by the testes differs from that by the ovaries. Competition data show that the uptake of the labelled hormone is real and also show the different rates of uptake by the gonads of male and female sea urchins.
It is concluded that 1-MA may exhibit differential effects on cell types due to their differentiated state and the seasonal variations of the organisms. The action of 1-MA is, therefore, multiple and not restricted to the gametes although its action would ultimately result in gamete maturation. 相似文献
Using
It is concluded that 1-MA may exhibit differential effects on cell types due to their differentiated state and the seasonal variations of the organisms. The action of 1-MA is, therefore, multiple and not restricted to the gametes although its action would ultimately result in gamete maturation. 相似文献
976.
CHARLES S. BURKS RICHARD L. STEWART Jr GLEN R. NEEDHAM RICHARD E. LEE Jr 《Physiological Entomology》1996,21(1):44-50
Abstract. Supercooling points and chill tolerance were compared among nymphs and adults of the ixodid ticks Dermacentor variabilis, Amblyomma americanum and Ixodes scapularis (Acari: Ixodidae).Supercooling points in the range of <-22 to -18°C were observed for nymphs, and -22 to -8°C for adults.The lower lethal temperatures observed under dry conditions, -14 to -10°C, were warmer than the supercooling points, but still much colder than -4.8°C, the lowest temperature recorded from a likely tick habitat in southwestern Ohio.Based on our experiments, spontaneous freezing and direct chilling injury are not significant mortality factors in these species in the field.Mortality was observed between -5 and -3°C for A.americanum and D.variabilis nymphs chilled for 2 h while in direct contact with ice.This mortality is probably due to inoculative freezing.Given the requirement for a rather humid microhabitat for off-host survival, these findings suggest that inoculative freezing is an important cause of overwintering mortality in these medically important species. 相似文献
977.
978.
Joo‐Oh KANG Dong Kwan JEONG Dong‐Kyu LEE Hyesook KANG Martha KIARIE‐MAKARA 《Entomological Research》2011,41(2):60-65
A granular formulation of 1.0% temephos (temephos G) was tested for its efficacy in mosquito larval control, residual effects and effects on non‐target microorganisms. Culex pipiens complex in septic tanks in Yangsan, Republic of Korea were used for this study. Microorganisms in the same septic tanks were used for study of non‐target organisms. After the application of temephos G at the rates of 2.0 and 5.0 mg/L to selected septic tanks, mortalities were recorded for 50 days. The effect of temephos G on non‐target organisms was studied by evaluating its effects on the bacterial populations in the treated septic tanks. It was observed that using 1.0% temephos G at a rate of 2.0 mg/L resulted in 100% mortality against Cx. pipiens larvae by the eighth day after treatment. The residual activity of temephos G was observed to continue for a time; for example 29 days after treatment, average larval mortality rates of >68.0% were observed for both concentrations. At the 50th day after treatment, the mortality rates of the Cx. pipiens larvae were observed to decrease to below 42.7% for both concentrations. Application of temephos G did not have significant effects on the bacteria populations in the septic tanks. Since temephos did not seem to have any major effects on the microorganisms, it was concluded that it is a safe and effective larvicide to use in the septic tanks at a rate of 2.0–5.0 mg/L of 1.0% temephos G. 相似文献
979.
A LEXICON FOR FLAVOR DESCRIPTIVE ANALYSIS OF GREEN TEA 总被引:4,自引:2,他引:2
980.
Yushan cane ( Yushania niitakayamensis ) is distributed in southeast Asia. In Taiwan, the species occurs in mountains 1000–3600 m above sea level. The species appears to spread mainly by rhizomes and flowers only rarely. Nine locations across its distribution range in Taiwan were sampled. Locations at higher altitudes generally consist of grassland and forest undergrowth habitats while those of lower altitudes generally consist of forest undergrowth only. Thus two sampling sites (montane grassland and forest undergrowth) were selected from each location at higher altitudes while only one sampling site was selected from each location at lower altitudes, resulting in a total of 13 sampling sites. Within each sampling site, 20 individual plants were sampled. The results of the cluster analysis and the principal coordinate analysis based on random amplified polymorphic DNA (RAPD) indicated that the populations are generally differentiated according to geographical separation and altitudinal differences that interrupt gene flow. The populations at higher altitudes, where the species is distributed somewhat contiguously, were found to be more similar genetically. Analysis of molecular variance ( AMOVA ) revealed that the among-location, between sampling sites within location, and among individuals within sampling site components accounted for 15.27%, 4.80% and 79.93% of the total variance, respectively. For locations with two sampling sites, two-level AMOVA revealed that the diversities between sampling sites (sun and shade habitats) within locations ranged from 2.91% to 7.99% of the total diversity. Random permutation tests revealed that these diversities were significant, implying that there is microgeographic differentiation due to habitat differences. 相似文献