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21.
本研究以额济纳绿洲四道桥超级站为研究区,结合2018—2019年涡度通量、气象数据和2017—2020年Sentinel-2遥感影像,分析通量塔总初级生产力(GPP)与环境因子的关系,评估12种遥感植被指数对柽柳灌丛长势模拟和关键物候参数提取的适用性。采用7参数双逻辑斯蒂函数(DL-7)+全局模型函数(GMF)拟合GPP和各植被指数生长曲线,并逐年提取生长季始期(SOS)、生长季峰期(POS)和生长季末期(EOS)3种关键物候参数。结果表明: 有效积温(GDD)和土壤含水量是影响柽柳灌丛物候动态的主要环境因子。与2018年相比,2019年由于气温较低,SOS前的积温累积速率较慢,柽柳灌丛需要更长时间的热量积累来进入生长季,从而导致2019年SOS比2018年晚。在SOS与POS之间,2018和2019年水热条件相似,但2019年POS比2018年晚8 d,可能是2019年SOS较晚所致。POS以后,2019年较高的GDD和较低的土壤含水量使柽柳灌丛遭受水分胁迫,导致其生长季后期时间缩短。标准化的Sentinel-2植被指数与10:00—14:00 GPP均值的线性回归结果表明,宽波段植被指数中的增强型植被指数和窄波段植被指数中的叶绿素红边指数、倒红边叶绿素指数、红边归一化植被指数(NDVI705)能够较好地反映与柽柳灌丛GPP具有较高的一致性。柽柳灌丛SOS和EOS的遥感提取结果表明,Sentinel-2窄波段植被指数比宽波段植被指数的准确性更高,尤其是修正叶绿素吸收反射率指数提取SOS最准确,MERIS陆地叶绿素指数提取EOS最准确;Sentinel-2宽波段植被指数提取POS的准确性更高,尤其是两波段增强型植被指数和植被近红外反射率指数最准确。综合所有物候参数来看,NDVI705综合表现最佳。  相似文献   
22.
Lizard beetles (Erotylidae, Languriinae, Languriini) are known as stem borers of plants and contain agricultural pests and endangered species, but their species–host plant associations have been poorly documented. Here we investigated the larval host plants of two species of the genus Tetraphala Strum, T. collaris (Crotch) and Tetraphala sp. occurring in Taiwan. Females of T. collaris excavated living leafstalks and stems of the herbaceous dicot, Sambucus chinensis (Adoxaceae) using their mandibles for oviposition. We observed the eggs and early-instar larvae inside and nearby oviposition holes and late-instar larvae inside stems, suggesting that T. collaris uses living leafstalks and stems of S. chinensis as oviposition substrate and the larvae tunnel into stems with feeding on the tissues. Similarly, females of Tetraphala sp. excavated living leafstalks of the fern, Pteris wallichiana (Pteridaceae) using their mandibles for oviposition. We observed the eggs and early-instar larvae inside and nearby oviposition holes. When reared in laboratory, a larva reached adulthood inside the leafstalk. These results indicated that Tetraphala sp. uses living leafstalks of Pt. wallichiana as oviposition substrate and the larvae complete their development within. This study revealed that the genus Tetraphala contains both fern- and dicot-users during larval period. Further study is needed to clarify the evolutionary process of host plant use of languriines. Additionally, the host plant list of Languriini is provided.  相似文献   
23.

The shrimp Penaeus chinensis at moult stage Do were subjected to one of the three following treatments: bilateral eyestalk ablation, amputation of the fifth pair of pereiopods, and both of the above treatments. Two consecutive ecdyses after treatments were followed. Intact animals served as control. Precocious moulting was exhibited in all treated groups. Eyestalk ablation shortened the time to the first ecdysis more than does limb amputation. Additive effect was found in shrimps receiving both treatments. The duration between the first and second ecdyses in treated shrimps was shorter than that of intact animals, but the durations in the three treated groups were not significantly different from one another. Regenerates of limbs appeared after the second ecdysis following limb amputation. Further, change of body colour from black and green to red and white was observed in shrimps with eyestalk ablation.  相似文献   
24.
Abstract

Curcumin (1) is a potent antioxidant and antitumor natural product. In spite of its efficacy and safety, its clinical use is hindered mainly by poor water solubility and bioavailability. Structural modification to introduce hydrophilic functions is a promising approach to resolve this problem. In the present study we first found that curcumin could be efficiently converted into glucosides by filamentous fungi including Rhizopus chinensis IFFI 03043, Absidia coerulea AS 3.3389 and Cunninghamella elegans AS 3.1207. Curcumin 4′-O-β-d-glucoside (2), together with hexahydrocurcumin (3), was isolated from a preparative-scale biotransformation with R. chinensis IFFI 03043 and characterized fully by NMR and MS. A time-course study revealed that curcumin could be efficiently converted into curcumin 4′-O-β-d-glucoside within 8 h when administered at 0.05 mmol L?1 and the productivity was 57%. Additionally, the biotransformation products of curcumin by different fungal strains were analyzed by LC/MS. At least 15 metabolites were detected, and the predominant biotransformation reaction was glucosylation. This study provides a simple, efficient and less expensive approach for the preparation of curcumin glucosides. The introduction of the glucosyl function might be able to enhance the bioavailability of curcumin.  相似文献   
25.
Field evaluation of some botanical formulations like Neem Azal T/S, Neem Azal T/S + TS/fort and petroleum ether extract of Curcuma longa for the management of different pests attacking broad bean crop in a new reclaimed area at El- Noubaria and under storage conditions has been carried out. All tested formulations could be considered efficient in controlling Aphis craccivora infesting broad bean under field conditions. As to the leafminer, the number of living Liriomyza trifolii larvae decreased significantly compared to non-treated control. The number of living larvae continued to decrease until seven days post-treatment after which an increase in their number was noticed after 14 days post-treatment. Neem Azal T/S + additive (TS/fort) ranked first in comparison to other treatments for the control of aphids and leafminers attacking broad bean in the field either by killing, deterrent or antifeedant effect. The yield of treated crop increased significantly in comparison to the control. Another spray was used before harvesting the crop with the same formulations for protection of the stored crop. Neem Azal T/S with adjuvant (TS/fort) protected broad bean seeds from weevil attack for one year. Petroleum ether extract of C. longa could protect the stored crops for two months only. The percentage weight loss in one kg stored seeds treated in the field with Neem formulation + adjuvant was very small compared with those seeds treated with petroleum ether extract of C. longa and control.  相似文献   
26.
The fumigant effect of Mentha piperita and Ocimum basilicum oils and their mixture against adults and eggs of Callosobruchus chinensis (L.) was evaluated. Bioassay experiments showed that Ocimum basilicum oil was significantly effective against adult and egg stage which was the least effective. However, in the fumigant toxicity experiments against adult stage, Ocimum basilicum oil at a dose of 1.0 μl/38.5 ml air caused 100% mortality (LC50 = 1.88), the mixture of both oils at a dose of 6.0 μl/38.5 ml air caused 100% mortality (LC50 = 10.3) and Mentha piperita oil at a dose of 80.0 μl/38.5 ml air caused 80.0% mortality (LC50 = 41.224) during a one day exposure period. Regarding the oviposition deterrent activity, Ocimum basilicum oil achieved 100% oviposition deterrent (at a dose of 0.5 μl/38.5 ml air) followed by the mixture of Mentha piperita and Ocimum basilicum oils, which achieved 71.22% oviposition deterrent (at a dose of 1.0 μl/38.5 ml air) and Mentha piperita oil, which achieved 39.6% oviposition deterrent (at a dose of 5.0 μl/38.5 ml air). The essential oils and their mixtures studied here determined a significant decrease in the number of eggs hatched and in the emergence of adults. The eggs failed to hatch on using Ocimum basilicum oil at a dose of 0.6 μl/38.5 ml air. However, the number of eggs hatched decreased to 7.4 on using a mixture of oils at a dose of 2.0 μl/38.5 ml air and 14.0 with Mentha piperita oil at a dose of 80.0 μl/38.5 ml air compared with 25.0 eggs hatched in the control experiments. On the other hand, the percentage reduction in emerging adults were 100% for Ocimum basilicum oil, 90.9% for a mixture of the two oils and 72.7% for Mentha piperita oil. Results showed that Ocimum basilicum oil and Ocimum basilicum oils plus Mentha piperita oils in blend are potential alternatives to synthetic fumigants in the treatment of durable agricultural products. Successful adoption of plant oils in the protection of food commodities promises an eco-friendly option compatible with international biosafety regulations.  相似文献   
27.
本文对‘香槟’月季(80sachinensis‘Xiangbin’)的组织培养技术和诱导试管开花进行了研究。结果表明:以茎段为外植体能诱导获得无菌苗,适宜的启动培养基为MS+6-BA1.0mg-L-1+IBA0.1mg·L-1,幼芽继代增殖的最佳培养基是MS+6.BA1.0mg·L-1。+IBA0.1~0.2mg·L-1,诱导生根的适宜培养基为1/2MS+NAA0.3mg·L-1,生根率达80.0%。诱导试管开花的适宜培养基为MS+6.BA0.5mg·L-1+NAA0.1mg·L-1最适宜的诱导试管开花的蔗糖含量是30g·L-1;在三角瓶中培养,试管花可以正常开放,在培养瓶中培养花芽不能正常开放;MS培养基中增加2倍磷的含量,可以提高花芽诱导率,为25.O%;诱导试管开花的最适培养条件为温度21℃,光照强度80~100μmol·m-2.s-1,光照时间16h—d-1。  相似文献   
28.
The study was conducted to evaluate the effects of dietary supplementation with different levels of two extracts, an aqueous extract of Ligustrum lucidum (AELL), and an ethanol extract of Schisandra chinensis (EESC) on growth performance, parameters of antioxidative status and spleen lymphocyte proliferation of broilers, respectively. The results showed that neither AELL nor EESC had significant effects on growth performance of broilers. However, malondialdehyde concentration in heart and liver of the broilers were significantly decreased by feeding AELL or EESC. Superoxide dismutase activity in heart, liver, and kidney of broilers were improved by feeding different dosages of AELL or EESC. In contrast, glutathione reductase activity in serum, heart and kidney of broilers was not affected by experimental treatment. In addition, spleen lymphocyte proliferation of broilers was significantly enhanced by feeding different dosages of AELL or EESC. In conclusion, the results suggested that either AELL or EESC may improve antioxidant status and immune function of broilers.  相似文献   
29.
蠋蝽是农林业上一种重要的捕食性天敌昆虫,可以捕食美国白蛾、马铃薯甲虫、棉铃虫、盲椿象等多种害虫。本文对近些年来蠋蝽的形态学、生物学、人工饲养、营养基因组学、储存技术、控害能力等作一阐述,并对蠋蝽应用前景进行了展望。  相似文献   
30.
不结球白菜种质资源对TuMV的抗性鉴定与评价   总被引:1,自引:0,他引:1  
分别利用苗期人工接种鉴定及ELISA检测方法,对127份不结球白菜种质资源进行芜菁花叶病毒(TuMV)的抗性鉴定。结果显示,苗期人工接种鉴定的病情指数(DI)分布在3.55~95.68之间,不同种质间表现出较大的抗性差异。不同抗性级别的次数分布图基本符合正态分布,略向感病区域偏离。基于病情指数的聚类分析结果与抗病性分级基本一致。通过苗期鉴定共筛选获得高抗TuMV的不结球白菜种质6份,抗病种质13份,其主要农艺性状表现出一定的多样性。其中叶面皱缩和具有刺毛的抗病材料所占比例较高,可能与TuMV抗性存在一定的相关性。ELISA检测结果显示,117份供试种质的P/N值分布在3.10~25.37之间,不同种质间表现出病毒含量的差异,但与DI值未呈现明显相关性,可作为抗病材料筛选的辅助指标。  相似文献   
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