排序方式: 共有47条查询结果,搜索用时 31 毫秒
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天鹅湖大叶藻种苗补充情况调查 总被引:2,自引:0,他引:2
本研究以山东荣成典型潟湖——天鹅湖内的大叶藻(Zostera marina L.)海草床为研究对象,从2015年3月到6月对大叶藻种子萌发形成的幼苗进行进了月度调查,包括春季大叶藻种苗的密度、株高、叶鞘高、叶数、叶宽以及分枝情况。结果表明,天鹅湖大叶藻种子在3月即开始萌发,但萌发量较少,种苗密度较低;4月种子大量萌发,种苗密度不断升高,并达到峰值,为(481.77?303.42)株/m2;5月份种子萌发结束,种苗密度下降,同时开始克隆生长;6月份种苗不断生长,分枝数增多,种苗开始出现有性生殖枝。至此,春季种苗的萌发过程结束,进入有性生殖过程。 相似文献
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Dileep Kumar Gupta Pradeep Kumar Ajeet Kumar Vishwakarma Prashant K. Srivastava 《国际地球制图》2018,33(6):602-611
The vegetation water content (VWC) of kidney bean crop is retrieved using ground-based multi-temporal, multi-angular and co-polarized scatterometer data at X-band. An outdoor crop-bed was prepared to observe the scatterometer response at HH- and VV-polarizations in the angular range from 20° to 70°. The trend of scattering coefficient is found to decrease for the entire angular range. The present study is carried out to investigate the retrieval for VWC of a kidney bean crop at its nine different growth stages by an empirical relation based on least square optimization method using scatterometer data. The results are found promising for the retrieval of the VWC of kidney bean crop at its several growth stages. 相似文献
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近年来美国和智利等国家新发现了大量赋存在粘土岩中的锂资源,该类锂资源主要是由火山灰蚀变而成。火山灰沉积水解形成的绿豆岩,广泛分布于我国西南地区,其是否存在锂的富集现象值得研究。笔者对重庆铜梁地区绿豆岩开展了调查研究,通过X射线荧光光谱仪和等离子质谱仪分析,发现绿豆岩中钾的平均含量为8.77%,锂的含量可达663×10~(-6),相当于0.14%的Li_2O含量,远高于固体、露采盐类矿的边界品位0.06%;稀土元素总量可以达到500×10~(-6),接近离子吸附型矿的边界品位。X射线衍射分析显示绿豆岩主要含有石英、长石和粘土矿物,其中粘土的主要成分为伊蒙混层和少量伊利石。伊蒙混层含量占比高的样品较占比低的样品Li的含量偏高。结合粘土及锂的物理化学特性,推断绿豆岩中的Li呈离子形态被粘土矿物吸附。如果这些锂资源能够被综合利用,势必将会产生巨大的经济效益。 相似文献
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LIU Ruizhi JIANG Xiaolu GUAN Huashi LI Xiaoxia DU Yishuai WANG Peng MOU Haijin 《青岛海洋大学学报(英文版)》2009,(3):303-311
In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato (Lycopersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6molL^-1 PEG-6000 solution for 6h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings. 相似文献
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采用连续形态分析方法研究了重庆市城乡交错区土壤中Cd的形态分布及其与莴笋吸收Cd量的关系.结果表明,研究区土壤和莴笋中Cd污染严重,土壤各形态Cd总体分布特征为:残渣态Cd>有机质结合态Cd>离子交换态Cd>碳酸盐结合态Cd>铁锰氧化物结合态Cd>水溶态Cd,其中活性较强的交换态Cd(包括水溶态Cd和离子交换态Cd)比重较大.Cd在土壤中的分布与土壤中的物理性粘粒及粉粒含量密切相关.而在土壤各形态Cd中,离子交换态Cd具有较高的生物有效性.研究区土壤和蔬菜中Cd污染已经较严重,建议加强城乡交错区的环境综合管理. 相似文献
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经发酵的酒精废渣用于沙地改良的试验研究 总被引:2,自引:0,他引:2
在科尔沁沙地试验了经发酵的酒精废渣对沙地土壤理化性状及作物生长和产量的影响。结果表明:该废渣中含有较高的有机质和作物所需的氮磷养分,施入沙地土壤后,经过一个生长季,土壤的保水性能明显提高、容重降低0.02~ 0.16 g·cm-3、pH值下降0.05~ 0.75、有机质增加0.05%~ 0.58%、全磷和全氮分别增加0.002%~0008%和0.002%~ 0.072%;适量施用该废渣可以提高作物的产量,但过量施用对小麦和荞麦生长发育有抑制作用。 相似文献
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采用对比试验,研究了红砂(Reamuria songarica (Pall.))大田容器育苗的容器选择、种子处理、覆土厚度、覆盖保护和灌水方式等措施对出苗率、成苗率和容器苗质量的影响。结果表明:红砂适宜的育苗容器为底部多孔的大规格容器,适宜的覆土厚度为0.3~0.6 cm,覆盖材料的适宜遮光率应控制在60%以下;以遮光率60%的遮荫网为例,适宜的覆盖时间为20~30 d左右;细质地的河沙表面覆盖是较好的覆盖方式。育苗容器和覆盖方式对幼苗质量有显著影响。覆土厚度和覆盖时间对出苗率和成苗率均有显著影响;覆盖方式仅对出苗率有显著影响;种子处理和灌水方式对出苗率、成苗率均无显著影响,但从生产的经济实用性及容器苗质量方面综合评价,种子机械处理和漫灌+喷灌灌水方式更符合生产推广要求。 相似文献