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121.
122.
ABSTRACT Elsholtzia splendens Naki has been identified as a copper (Cu) geobotanical indicator. In this study, the effects of Cu supply levels (control, 100, 200, 400, 600, 800, 1000, 1200 mg kg1) on the growth and Cu accumulation in E. splendens were studied in one pot experiment. The results showed that no reduction in shoot height and dry weight was noted when the plants were grown at Cu supply levels up to 1000 mg kg?1 in soil. Slight stimulation on shoot growth was noted at Cu levels ≥ 100 mg kg?1. Copper concentration in shoots and roots increased with increasing Cu levels, and reached a maximum of 1751 and 9.45 mg kg?1 (DW) at 1200 mg Cu kg?1. The amount of Cu accumulated in the roots and shoots were 313 and 22 μ g plant?1 at external Cu levels of 1000 and 800 mg kg?1, respectively. The shoot/root Cu ratios ranged from 0.005 to 0.008 and more than 92% of the total Cu taken up by E. splendens was accumulated in roots. Furthermore, Cu concentrations in roots and shoots were significant and positively correlated with total soil Cu, water, ammonium nitrate (NH4NO3), ammonium (NH4)-acetate, and ethylenediaminetetraacetic acid (EDTA) extractable Cu. These results indicate that E. splendens can considered as a Cu tolerant and accumulated plant, and root is the major part for accumulation of Cu in E. splendens. 相似文献
123.
Julie Ramírez Martínez Martha Cárdenas Toquica Marcela Guevara-Suarez Diannefair Duarte Laura Daniela Victorino Jimenez Bibian Katherine Argüello Bernal Edwin Gutiérrez Rodríguez Silvia Restrepo Restrepo 《Plant pathology》2021,70(7):1695-1707
The study of oomycetes associated with crops is highly important due to the economic losses they might cause. In cacao, the genus Phytophthora has been extensively studied, but little is known about other genera and species of oomycetes associated with this plant. This study aimed to determine the oomycetes’ diversity present in Colombian cacao crops. A total of 146 isolates were obtained from diseased plants and soil in 11 departments. Analysis of internal transcribed spacer (ITS) and cytochrome oxidase subunit I (coxI) sequences was performed along with the assessment of morphological characteristics. Nine species were identified, distributed in four genera: Phytophthora (P. palmivora, 54%; P. nicotianae, 1%), Phytopythium (Phy. chamaehyphon, 15%; Phy. cucurbitacearum, 9%; Phy. vexans, 7%; Phy. helicoides, 1%), Globisporangium (G. splendens, 3%), and Pythium (Py. delicense, 1%; Py. inflatum,1%). Additionally, an unidentified and possibly new species of Phytophthora (5%) and three unidentified species of Phytopythium (3%) were found. This is the first report of Globisporangium, Phytopythium, and Pythium in cacao crops of Colombia and the first report of the species Phy. chamaehyphon in the country. Interestingly, some isolates of Phytopythium spp. were isolated from necrotic leaves and vascular section of stems, which may suggest a role in cacao diseases traditionally associated with Phytophthora. Also, it is proposed that the new species of Phytophthora may be contributing significantly to black pod disease in Colombian cacao crops, and we highlight that the study of P. palmivora is urgent because of its distribution all over the country. 相似文献
124.
《Plant Production Science》2013,16(1):95-104
AbstractIn Japan, soybean is usually cultivated in fields that have been converted from rice paddies, and poor seedling establishment due to pre-emergence seedling damping-off is often observed during the rainy season. In this study, the factors that cause the damping-off in flooded soil were investigated under high soil moisture conditions in a greenhouse and in agricultural fields. In sterilized soil sampled from a soybean field, seedlings emerged well under 48-hr flooded conditions. In unsterilized soil, soybean seeds treated with the fungicide, mancozeb+metalaxyl exhibited much higher emergence rates even under 48-hr flooded conditions than the seeds treated with oxytetracycline +streptomycin, benomyl, or flutolanil. Pythium, Phytophthora, Mucorales, Trichoderma, Geotrichum-like microorganisms, and some fungi producing conidia in a false head, were isolated from decayed seedlings. Of the isolated microorganisms, oomycete microorganisms, Pythium helicoides, other Pythium sp., and Phytophthora sp. were pathogenic to soybeans under flooded conditions. As the length of the flooding period increased, pre-emergence seedling rot also increased. However, the pathogenic oomycetes rarely caused pre-emergence seedling rot under conditions without flooding. Furthermore, under flooded conditions, the damage caused by these pathogens was reduced by treating the seeds with mancozeb+metalaxyl. These results indicate that oomycete microorganisms are involved in pre-emergence seedling damping-off under flooded soil conditions. 相似文献
125.
J. C. J. van Zon 《国际虫害防治杂志》2013,59(2):179-185
Abstract Conventional methods of aquatic weed control meet increasing objections on economic and/or environmental grounds. An alternative approach is the use of grass carp (Ctenopharyngodon idella Val.), a herbivorous fish. This biological method has mainly been used in Europe and the USA, but since 1976 an Egyptian‐Dutch project has studied the potential of this approach for the Egyptian irrigation systems. All aspects of the production and use of grass carp have been studied and evaluated, Egyptian personnel have been trained, a large‐scale breeding station has been established and practical use of the technique has begun. The programme has shown that a stocked grass carp population not only provides effective weed control, but it also increases the protein production in Egyptian waterways substantially. If managed well, this production can provide continuous revenues that far outweigh the costs of weed control. The necessary management techniques developed are mainly based on yearly restocking with grass carp and cooperation between irrigation authorities and professional fishermen. The experience described in this paper will be of interest to many other countries. 相似文献
126.
青海湖芨芨草干草原植被退化对土壤温湿特征的影响 总被引:2,自引:0,他引:2
芨芨草(Achnatherum splendens)干草原目前退化严重,但对土壤温湿特征的驱动机理仍不清楚。利用2011年连续观测资料分析环青海湖区域的芨芨草干草原原生植被和典型退化区域的0 cm、5 cm、10 cm、20 cm、40 cm和80 cm土壤温度和5 cm、10 cm、20 cm、40 cm和80 cm土壤容积含水量。结果表明:植被退化直接导致0 cm和5 cm表层土壤温度日极大值显著升高了39.04%和13.91%,温度日极小值显著降低,温度日较差升高;而10 cm以下温度日特征无显著响应。原生植被区0 cm逐日土壤温度在植物生长季(5-9月)极显著降低,非生长季5 cm和10 cm则略高。芨芨草植被改变了土壤年均温度垂向扩散特征。植被退化间接导致土壤5 cm土壤容积含水量升高了35.20%,10 cm无差别,20 cm以下显著降低,同时降低了系统土壤含水量的时间稳定性。特征聚类分析结果表明,芨芨草干草原土壤温湿特征对植被退化的综合响应主要表现在7-8月。 相似文献
127.
笔者旨在通过筛选防治番茄茎腐病的有效药剂,为田间防治提供指导。室内测定了5 种杀菌剂对终极腐霉菌丝生长的抑制作用,恶霉灵、唑醚·代森联、硫酸铜钙、甲基硫菌灵和恶酮·霜脲氰为有效杀菌剂。研究结果表明:恶霉灵的EC50为0.364 mg/L,抑菌效果最好;唑醚·代森联效果次之,EC50为9.247 mg/L,其他药剂防治效果相对较差。在田间药剂筛选试验中,70%恶霉灵可湿性粉剂与70%甲基硫菌灵可湿性粉剂组合防治效果为95.57%,均优于其它供试药剂组合,可应用于番茄茎腐病的田间防治。 相似文献
128.
129.
泰国斗鱼的胚胎发育及温度对胚胎发育的影响 总被引:1,自引:0,他引:1
观察了泰国斗鱼Betta splendens受精卵的形态和胚胎发育的过程,研究了温度对胚胎发育的影响。试验设置5个温度组(20、23、26、29、32℃),记录各温度下胚胎发育历时、孵化率和畸形率,共重复5次。结果表明:水温为20~32℃时,泰国斗鱼受精卵均能孵化,最适孵化温度为26~29℃。孵化温度T与孵化时间t呈负相关,相关方程为t=18878T-1.8528(R2=0.9811);泰国斗鱼胚胎发育的生物学零度为11.08℃,有效积温为659.39℃.h。 相似文献
130.
Sherif S. Ebada Victor Wray Nicole J. de Voogd Zhiwei Deng Wenhan Lin Peter Proksch 《Marine drugs》2009,7(3):434-444
Two new jaspamide derivatives 2 and 3, together with the parent compound jaspamide (1) have been isolated from the marine sponge Jaspis splendens collected in Kalimantan (Indonesia). The structures of the new compounds were unambiguously elucidated based on 1D and 2D NMR spectral data, mass spectrometry and comparison with jaspamide (1). The new derivatives inhibited the growth of mouse lymphoma (L5178Y) cell line in vitro with IC50 values of <0.1 μg/mL. 相似文献