Results 41 to 50 of about 7,553 (154)

不同土壤水分条件下侧柏幼苗的生理活动及氮素分配策略

open access: yesShuitu Baochi Xuebao, 2020
以北京地区3年生侧柏幼树为研究对象,采用温室内盆栽试验,设置5个不同土壤含水量水平,采用15N同位素自然丰度法研究不同水分条件下侧柏幼苗的生理活动、生物量分配及氮素吸收和分配情况。结果表明:(1)在水分胁迫下,侧柏单株净光合速率、呼吸速率、蒸腾速率均表现为最低值,随着干旱胁迫解除,含水量增加到正常值,各指标分别增加为原来的4.86,3.74,7.29倍,叶片含水量和叶面积分别增加了24.37%,23.69%;之后当土壤含水量超过正常值时,随着土壤水分含量的进一步增加,各指标略有下降。(2)在水分胁迫下 ...
王鑫   +5 more
doaj  

Accumulation Characteristics and Hydrological Effects of Litter in Mixed Robinia pseudoacacia Plantations [PDF]

open access: yes
[Objective] Studying the accumulation characteristics and hydrological effects of typical mixed Robinia pseudoacacia plantations is crucial for deeply investigating the water conservation capacity of artificial forests on the Loess Plateau.
CAO Zetao   +5 more
core   +1 more source

三种阔叶林凋落物的持水特性

open access: yesShuitu Baochi Xuebao, 2006
对火力楠、荷木和黎蒴的凋落物的储量、持水量、持水率和吸水速率进行了研究。结果表明,火力楠、荷木和黎蒴林地的凋落物干重分别为10488,5159,5583kg/hm^2。浸泡2h前凋落物持水量呈现火力楠林地〉黎蒴林地〉荷木林地,浸泡2h后为黎蒴林地〉火力楠林地〉荷木林地。3种林分中黎蒴林地的凋落物最大持水量在居首位,达17709kg/hm^2,火力楠林地居中,为16576kg/hm^2,荷木林地较小,为13374kg/hm^2。不同浸泡时间段的凋落物持水率均呈现黎蒴林地〉荷木林地〉火力楠林地。火力楠 ...
彭耀强   +4 more
doaj  

Seed Dormancy Mechanism and Ways to Accelerate Germination of Syagrus romanzoffiana and Arenga engleri [PDF]

open access: yes, 2005
本文以生产上发芽不整齐的皇后葵和香棕种子为材料,研究棕榈科植物种子的休眠机理及催芽技术。试验结果表明,皇后葵及香棕的果肉及胚乳中均含有发芽抑制物质,同一植株的种子发芽率及发芽力的差别还与种子的成熟度有关,用GA3 100mg/L或NAA 100mg/L浸种有利于提高发芽率。Using the seeds of Syagrus romanzoffiana and Arenga engleri as experiment materials,the dormancy mechanism of seed ...
杨盛昌, 梁育勤
core  

Effects of Salt Stress on Active Components, Antioxidant Capacity and Antioxidase Activity of Sesame during Germination [PDF]

open access: yes
To investigate the effect of salt stress on the germination of sesame, a mixed salt solution of sodium chloride and calcium chloride was used as the culture medium to analyze the changes and correlations in growth characteristics, total phenolic content,
Chengxiang WANG   +7 more
core   +1 more source

平原粉沙淤泥质海岸防护林土壤渗透特性的研究

open access: yesShuitu Baochi Xuebao, 2001
探讨了淤泥质海岸防护林土壤的渗透特性 ,指出同一林分土壤渗透速率差异较大 ,不同样地间土壤渗透速率的差异也十分显著。林地初渗速率大 ,在降雨初期能吸收大量降雨 ,稳渗时渗透速率未必比光板地大。林地土壤渗透过程符合对数曲线 ,相关系数达极显著水平 ...
胡海波 张金池
doaj   +2 more sources

荒漠草原典型植物群落枯落物蓄积量及其持水性能

open access: yesShuitu Baochi Xuebao, 2011
通过对荒漠草原4种典型植物群落(蒙古冰草群落、甘草群落、赖草群落、沙蒿群落)枯落物蓄积量的调查,结合室内持水试验,运用数理统计的方法分别得到4种典型植物群落枯落物的蓄积量、最大持水量、吸水速率等水文特征参数。结果表明:荒漠草原不同植物群落枯落物蓄积量在50.8~396.2g/m2,其蓄积量由大到小为蒙古冰草群落>甘草群落>赖草群落>沙蒿群落,与植物群落地上生物量变化是一致的;4种植物群落枯落物最大持水量存在一定差异,蒙古冰草群落、甘草群落、赖草群落、沙蒿群落枯落物最大持水量分别相当于0.934,0 ...
李学斌   +6 more
doaj  

环氧树脂在湿热环境中的老化特性与失效机理

open access: yesGaoya dianqi, 2022
环氧树脂在湿热环境下易吸水进而导致材料性能劣化,为了研究环氧树脂在湿热环境中的吸水特性与失效机理,文中对环氧树脂进行了湿热老化实验。实验结果表明,环氧树脂的吸水满足LangmuirEXT1等温吸附模型,饱和吸水率与温度成二次函数关系。环氧树脂吸水老化后,在微观层面,表面与切面出现很多微孔隙,孔隙数量与体积和老化温度成正相关;在宏观层面,老化后体积电阻率快速下降,而相对介电常数与介质损耗角增大,有低频色散现象。出现微小孔隙后,水分就会通过呼吸作用大量进入材料内部,内部孔隙的存在也会给水分提供存储空间 ...
李光茂   +5 more
doaj  

Flow Injection on-line Preconcentration with Anion-exchange-resin and Flame Atomic Absorption Spectrometric Determination of Trace Cadmium(阴离子树脂微柱在线预富集火焰原子吸收法测定痕量镉)

open access: yesZhejiang Daxue xuebao. Lixue ban, 1999
建立了流动注射在线微柱预富集-火焰原子吸收(FAAS)法测定天然水中痕量镉的体系.在溶液pH7.2条件下,8-羟基喹啉-5-磺酸与Cd2+形成的络阴离子被填有阴离子树脂的微柱吸附而富集.用1mol/L硝酸溶液洗脱树脂上所吸附的镉.洗脱液在线输入FAAS测定.当采样速率为24次/时,富集倍数为10,检出限0.5μg/L,工作曲线线性范围0~100μg/L,RSD为1.0%(n=11,Cd2+浓度为100μg/L).本体系已用于天然水样中痕量镉测定,回收率90%~106%.
MaoXueqin(毛雪琴)   +4 more
doaj   +1 more source

Research Progress on Extraction, Purification, Structural Modification, and Application of Phytoglycogen [PDF]

open access: yes
Phytoglycogen (PG), a carbohydrate polymer extracted from sugar-containing mutant seeds of plants, is a natural dendrimer-like glucan nanoparticle with high safety.
WANG Rui, LÜ Xiaorui, ZHANG Pengmin, WANG Wenxiu, SUN Jianfeng, MA Qianyun, WANG Jie
core   +1 more source

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