共查询到20条相似文献,搜索用时 31 毫秒
1.
亚热带樟树-马尾松混交林凋落物量及养分动态特征 总被引:1,自引:0,他引:1
选取亚热带典型的针阔混交林作为研究对象,从2009年至2011年每月进行凋落物的测定。结果表明:混交林年凋落物总量为(4634.723±337.1427) kg/hm2,且凋落叶(71.78%) > 凋落枝(26.24%) > 凋落碎屑(8.46%) > 凋落果(3.23%)。凋落总量的月变化趋势明显,在11月份达到了最大值1025.6 kg/hm2,而最小值出现在2月份138.606 kg/hm2。混交林凋落物中大量元素、微量元素含量差异显著。大量元素含量大小顺序:C > N > Ca > K > S > Mg > P,微量元素的含量大小顺序:Mn > Fe > Zn > Pb > Cd > Cu > Ni > Co。C/N的特征是:枝(66.96) > 果(63.48) > 叶(40.62)。森林凋落物养分的含量直接决定了其养分的归还量。樟树-马尾松混交林凋落物养分归还总量为80.936 kg/hm2。混交林凋落物各元素养分归还量大小顺序特征是:N > Ca > K > S > Mg > P > Mn > Fe > Zn > Pb > Cd > Cu > Ni > Co。各组分养分归还特征是:叶(67.469 kg/hm2) > 枝(14.928 kg/hm2) > 果(2.361 kg/hm2)。混交林中N的年归还量为40.964 kg/hm2,其中凋落叶的N归还量较大为34.877 kg/hm2。 相似文献
2.
Using both topical application and substrate (sand) treatments the toxicities of seven new generation soil termiticides were evaluated to determine the LD50 and LC50 against two economically important subterranean termite species, eastern subterranean termite, Reticulitermes flavipes (Kollar), and Formosan subterranean termite, Coptotermes formosanus Shiraki. The lethal dose toxicity (LD50) rankings for R. flavipes from highest to lowest were: fipronil > bifenthrin > chlorantraniliprole > cyantraniliprole > imidacloprid > chlorfenapyr > indoxacarb; the rankings for C. formosanus were fipronil > imidacloprid > chlorantraniliprole > cyanthraniliprole> bifenthrin > chlorfenapyr > indoxacarb. The respective lethal concentration toxicity (LC50) rankings were fipronil > bifenthrin > chlorfenapyr > indoxacarb > cyantraniliprole > chlorantraniliprole > imidacloprid for R. flavipes; and fipronil > chlorfenapyr > bifenthrin >imidacloprid > cyantraniliprole > chlorantraniliprole > indoxacarb for C. formosanus. The study provides an opportunity to directly compare toxicity, action speed, and bioavailability among this group of newer generation soil termiticides. 相似文献
3.
采用差热分析系统(DTA)对8个主栽酿酒葡萄品种的芽和根系进行低温放热分析(LTE),建立各品种芽、根系韧皮部及木质部的温度-伤害度(LT-I)回归方程,评估不同品种的根系及芽抗寒性.结果表明: 8个品种的根系韧皮部伤害度50%的温度从高到低为马瑟兰>品丽珠>赤霞珠>小芒森>霞多丽>蛇龙珠>贵人香>熊岳白;不同品种木质部伤害度50%的温度从高到低为马瑟兰>霞多丽>赤霞珠>小芒森>品丽珠>蛇龙珠>贵人香>熊岳白;芽伤害度50%的温度从高到低为赤霞珠>小芒森>蛇龙珠>品丽珠>霞多丽>贵人香>马瑟兰>熊岳白.利用模糊隶属函数值法综合评价根系及芽的抗寒性,马瑟兰根系的抗寒性最差,熊岳白根系的抗寒性最好;赤霞珠、品丽珠、小芒森和蛇龙珠芽的抗寒性最差,贵人香和熊岳白芽的抗寒性最好. 相似文献
4.
对密云水库北京集水区板栗林主要养分元素循环进行了研究。结果表明,22年生板栗林的生物量为38638kg·hm-2;板栗林5种主要养分元素N、P、K、Ca、Mg贮存量为315.38kg·hm-2,各器官中5种元素贮存量大小排序是干>枝>根>叶>花>果苞>果。板栗林生态系统乔木层每年从土壤中吸收的5种养分元素量为79.17kg·hm-2,吸收量占0~30cm土层5种养分元素总量的0.15%,占0~30cm土层中5种元素有效养分量的1.95%。年吸收量中存留量为11.25kg·hm-2,枯落物归还量为58.08kg·hm-2。雨水及雨水淋溶输入到板栗林生态系统的养分元素量为38.63kg·hm-2,果实输出量为9.84kg·hm-2。雨水和雨水淋溶量与枯落物归还量之和大于吸收量,表明研究期间板栗林生态系统养分元素的收入略大于支出,5种元素的吸收系数排序为N>P>K>Ca>Mg,利用系数排序为K>N>Mg>P>Ca。循环系数排序为K>N>P>Mg>Ca。周转期排序是Ca>P>Mg>N>K。 相似文献
5.
Phillips CJ Wojciechowska J Meng J Cross N 《Animal : an international journal of animal bioscience》2009,3(8):1152-1166
The opinions of seven respondent groups about the relative importance of different practices pertaining to the welfare of Australian beef cattle, sheep and goats were surveyed. Respondent groups comprised farmers, livestock transportation representatives, veterinarians, meat processors, animal welfare advocates, animal welfare scientists and government officers. The survey consisted of a web-based adaptive conjoint analysis questionnaire, which was administered to a sample population that was selected randomly for large respondent groups and comprehensively for small groups. The hierarchy of opinion concerning the importance of the different beef cattle practices was: stockmanship > ground (road and rail) transport > spaying > food supply > dehorning > stunning > shelter > identification > pretransport food and water deprivation > castration > sea transport > mustering > confinement. For sheep/goat practices the hierarchy was: parasite control > mulesing > shelter > stockmanship > tail docking > ground transport > feeding > predation > stunning > castration > pretransport food and water deprivation > sea transport > mustering. The method of performing invasive procedures was perceived as less important than the provision of pain relief. Differences in opinion were evident between respondent groups, with animal welfare advocates tending to focus on painful procedures more than those with direct involvement in the industry. 相似文献
6.
Human, rat, Xenopus, and Drosophila (DPx2540 and DPx6005) peroxiredoxin cDNAs were cloned and expressed in Escherichia coli. The recombinant enzymes were compared with respect to enzymatic activity toward various substrates and protection of plasmid DNA from the Fenton reaction products. The activity toward H2O2 decreased in the following order: DPx2540 > human Prx6 > Xenopus Prx6 > rat Prx6 > DPx6005. The activity toward tret-butyl hydroperoxide decreased in the following order: DPx2540 = DPx6005 > rat Prx6 > Xenopus Prx6 > human Prx6. The efficiency of plasmid DNA protection from oxidative damage mediated by the Fenton reaction decreased in the order of DPx2540 > DPx6005 = rat Prx6 = human Prx6 > Xenopus Prx6. The optimal temperature for activity of all enzymes was 37°C. Peroxiredoxins from rat, Xenopus, and Drosophila (DPx6005) retained no less than 50% of their activity in a wider temperature range (10–50°C) as compared with the human and Drosophila (DPx2540) enzymes (25–45°C). The thermostability of the enzymes decreased in the following order: DPx6005 = rat > human > Xenopus > DPx2540. The results confirmed a negative correlation between the activity and stability of peroxiredoxin 6, especially in the case of the Xenopus and Drosophila enzymes. 相似文献
7.
Pinus tabulaeformis Carr. forest, the dominant community in Ziwuling Mountain lying in the hilly loess region, was studied for its nutrient distributions and bio-cycle characteristics in both natural and artificial forms. The results showed that the changes in the nutrient contents for different components in the same Pinus tabulaeformis Carr. forest stood in the order of needles > branches > bark > roots > bole. The aboveground nutrient elements in needles, branches, bark bole and litterfalls stood in the order of Ca > N > K > Mg > P, but the nutrients stored in the soil stood in the order of Ca > K > Mg > N > P. The accumulated amounts of nutrients increased first and then decreased with the increased age of the forest. The nutrient amounts reached their maximum when the stand was 30 years old, and decreased greatly when it was 50 years old. The 30-year-old artificial Pinus tabulaeformis Carr. forest had the highest annual accumulated amount of nutrients, and different stands stood in the order of II > III > IV > I. Comparatively, annual accumulated nutrients in different components stood in the order of needles > branches > roots > bark > bole. It was also suggested that the amounts of nutrients annually taken in from and retained in the natural Pinus tabulaeformis Carr. forest were significantly higher than those in artificial forests. The coefficients of nutrient use in various Pinus tabulaeformis Carr. stands stood in the order of Ca > Mg > N > K > P, but the nutrient use efficiency (NUE) of the same element decreased with increased age of the forest. There were no differences in the utilization coefficient and the turnover period of nutrients in both natural and artificial matured Pinus tabulaeformis Carr. forests. 相似文献
8.
松嫩平原盐渍化区土壤的微域特征 总被引:3,自引:2,他引:1
通过野外定位观测和室内分析,探讨了松嫩平原盐渍化区土壤的微域特征.结果表明:研究区由高平地、微坡地、洼地边缘和洼地4种微地貌单元组成.洼地发育均腐土,洼地边缘、微坡地和高平地发育碱积盐成土.高平地土壤的碱土碱化层出现在15~30 cm,碱化度(ESP)60%.微坡地土壤表层的ESP最大可达75%.洼地边缘的ESP分布在10~30 cm土层,最大为30%~40%.洼地的土壤几乎没有碱化层.研究区不同微地貌部位发育的土壤水分特征曲线存在明显差异.微坡地土壤饱和含水率最大仅为25%,而洼地土壤0~10 cm饱和含水率高达45%.不同微地貌单元的冻融过程存在明显的差异.微坡地和洼地的最大冻结深度分别为157和136cm.冻结期,洼地土壤表层含水率由冻结前的20%增加到50%.微坡地土壤表层含盐量变化在4个微地貌单元中最明显;冻融前后微坡地土壤表层含盐量增幅达80%. 相似文献
9.
Zhukov OD 《Ukrainski? biokhimicheski? zhurnal》1999,71(4):124-125
N-([1-14C]-palmitoyl)-ethanolamine distribution was studied in the rat tissues. The following sequence of the label inclusion into tissues by the way of decreasing the radio activity: adrenal > diaphragm > spleen > kidney > testis > lung > liver > heart > brain > plasma > erythrocytes was obtained. 相似文献
10.
鼎湖山南亚热带常绿阔叶林植物营养元素含量分配格局研究 总被引:37,自引:0,他引:37
在鼎湖山南亚热带常绿阔叶林中,植物叶片营养元素含量为N 0.946%-2.535%,P 0.030-0.127%,K 0.614%-1.833%,Ca 0.442%-1.995%,Mg 0.024%-0.188%。叶片各营养养元素间相关性较差,仅P与Mg及Mg与K之间存在显著的线性相关。叶片N元素平均含量在各层中的序列为:乔木Ⅲ〉乔木Ⅱ〉乔木Ⅰ〉灌木〉藤本〉草本;其它营养元素浓度随层次分配的规律性 相似文献
11.
The hypothesis that fish vision is influenced by the presence of a choroid rete mirabile (an oxygen-concentrating apparatus in the eye) and the Root effect was tested using the optomotor response in two nototheniid species from Antarctica. Pagothenia borchgrevinki , an active cryopelagic zooplanktivore, does not exhibit a major Root effect and the rete is absent. In contrast, the sluggish, benthic nototheniid, Trematomus bernacchii , possesses both a rete and a significant Root effect. Whole-eye ocular P O2 was higher in T. bernacchii (18.6 kPa) than in P. borchgrevinki (18.1 kPa) and the optomotor response of T. bernacchii was positively influenced by subtended angle on a moving background whereas P. borchgrevinki did not respond to any subtended angle (0–600 min of arc). The optomotor response of T. bernacchii may therefore have been facilitated by elevated ocular P O2 due to the presence of the choroid rete and the Root effect. 相似文献
12.
OBJECTIVE: Monoamine oxidase (MAO), the enzyme responsible for metabolism of monoamine neurotransmitters, has an important role in the brain development and function, and MAO inhibitors have a range of potential therapeutic uses. We investigated systematically in vitro effects of pharmacologically different antidepressants and mood stabilizers on MAO activity. Methods: Effects of drugs on the activity of MAO were measured in crude mitochondrial fraction isolated from cortex of pig brain, when radiolabeled serotonin (for MAO-A) or phenylethylamine (for MAO-B) was used as substrate. The several antidepressants and mood stabilizers were compared with effects of well known MAO inhibitors such as moclobemide, iproniazid, pargyline, and clorgyline. Results: In general, the effect of tested drugs was found to be inhibitory. The half maximal inhibitory concentration, parameters of enzyme kinetic, and mechanism of inhibition were determined. MAO-A was inhibited by the following drugs: pargyline > clorgyline > iproniazid > fluoxetine > desipramine > amitriptyline > imipramine > citalopram > venlafaxine > reboxetine > olanzapine > mirtazapine > tianeptine > moclobemide, cocaine > lithium, valproate. MAO-B was inhibited by the following drugs: pargyline > clorgyline > iproniazid > fluoxetine > venlafaxine > amitriptyline > olanzapine > citalopram > desipramine > reboxetine > imipramine > tianeptine > mirtazapine, cocaine > moclobemide, lithium, valproate. The mechanism of inhibition of MAOs by several antidepressants was found various. Conclusions: It was concluded that MAO activity is acutely affected by pharmacologically different antidepressants at relatively high drug concentrations; this effect is inhibitory. There are differences both in inhibitory potency and in mechanism of inhibition between both several drugs and the two MAO isoforms. While MAO inhibition is not primary biochemical effect related to their therapeutic action, it can be supposed that decrease of MAO activity may be concerned in some effects of these drugs on serotonergic, noradrenergic, and dopaminergic neurotransmission. 相似文献
13.
我们在法国西部的昂热市(Angers)试验研究了海甘蓝在不同生长时期内植株生长量、体内矿质营养元素含量、植株对不同营养元素的吸收量的动态变化。结果表明,海甘蓝在5个月生长期内的田间总生长量为12.22t·hm-2(干物质),移栽后各月内海甘蓝的生长量大小顺序为第五个月>第三个月>第二个月>第四个月>第一个月。海甘蓝植株体内B、S、Ca和P的含量以移栽后的第二个月最高,第五个月最低;Cu、Fe和Mn含量在第一个月最高,其它时期变化不大;Zn和Mn含量随移栽后的时间增加而降低;Na和K含量在整个生长季节内均无明显变化。在整个生长季节内,海甘蓝对各种矿质营养元素的总吸收量的大小顺序为K>Ca>S>P>Na>Fe>Mn>Zn>B>Cu。不同生长期,植株对多数营养元素的吸收量的大小顺序为第五个月>第三个月>第二个月>第四个月>第一个月 相似文献
14.
We analysed the concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in the water, sediments, fish and plants of the River Hindon, U.P., India, at seven sampling stations, in the year 1982. Considerable variation in concentration between water, sediments, fish and plants were noted. The concentration in the water was in the order Fe > Zn > Cr > Mn > Cu > Pb > Ni > Co > Cd, in the sediments, Fe > Mn > Zn > Ni > Cr > - Co > Cu > Pb > Cd; in a fish (Heteropnuestes fossilis) Fe > Zn > Mn > Pb > Ni > Co > Cu > Cd > Cr, and in a plant (Eicchornia crassipes) Fe > Mn > Zn > Ni > Cu > Cr > Pb > Co > Cd. 相似文献
15.
Supungul P Sootanan P Klinbunga S Kamonrat W Jarayabhand P Tassanakajon A 《Marine biotechnology (New York, N.Y.)》2000,2(4):339-347
16.
Y Hata M Watanabe O Shiratori S Takase 《Biochemical and biophysical research communications》1978,80(4):911-916
The fragmentation reaction of 2-para-substituted phenyl-N-methylaziridines in rat liver microsomes was studied. The relative reactivity against the substituent group, estimated from the amount of styrenes produced in liver microsomal solution, was para-Cl > para-Me > H > para-NO2 > para-OMe.The cytotoxic activity of these aziridines was also studied using HeLa cells and L-1210 mouse leukemia cells in free-floating culture. The order of cytotoxic activity with HeLa and L-1210 cells was Cl Me > H > NO2 OMe and Me > Cl OMe > H > NO2, respectively. The results indicated that the orders of cytotoxic activity and fragmentation reactivity for the parasubstituted aziridines have some parallel relationship. The nitrosomethane generated by fragmentation reaction of aziridine probably plays an important part in the biological activity of aziridines. 相似文献
17.
Nutrient distributions and bio-cycle characteristics in both natural and artificial Pinus tabulaeformis Carr. forests in hilly loess regions
下载免费PDF全文
![点击此处可从《农业工程》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Pinus tabulaeformis Carr. forest, the dominant community in Ziwuling Mountain lying in the hilly loess region, was studied for its nutrient distributions and bio-cycle characteristics in both natural and artificial forms. The results showed that the changes in the nutrient contents for different components in the same Pinus tabulaeformis Carr. forest stood in the order of needles > branches > bark > roots > bole. The aboveground nutrient elements in needles, branches, bark bole and litterfalls stood in the order of Ca > N > K > Mg > P, but the nutrients stored in the soil stood in the order of Ca > K > Mg > N > P. The accumulated amounts of nutrients increased first and then decreased with the increased age of the forest. The nutrient amounts reached their maximum when the stand was 30 years old, and decreased greatly when it was 50 years old. The 30-year-old artificial Pinus tabulaeformis Carr. forest had the highest annual accumulated amount of nutrients, and different stands stood in the order of II > III > IV > I. Comparatively, annual accumulated nutrients in different components stood in the order of needles > branches > roots > bark > bole. It was also suggested that the amounts of nutrients annually taken in from and retained in the natural Pinus tabulaeformis Carr. forest were significantly higher than those in artificial forests. The coefficients of nutrient use in various Pinus tabulaeformis Carr. stands stood in the order of Ca > Mg > N > K > P, but the nutrient use efficiency (NUE) of the same element decreased with increased age of the forest. There were no differences in the utilization coefficient and the turnover period of nutrients in both natural and artificial matured Pinus tabulaeformis Carr. forests. 相似文献
18.
The interaction of the mutant genes wellhaarig (we) and waved alopecia (wal) in mice was earlier demonstrated in our laboratory. The we gene significantly accelerates the appearance of alopecia in double we/wewal/wal homozygotes as compared to that in single +/+wal/wal homozygotes. It has been found in this work that the mutant gene angora-Y (Fgf5 go-Y ) weakens the effect of interaction of the we and wal genes. The first signs of alopecia appear in mice of the we/wewal/wal genotype at the age of 14 days, in triple Fgf5 go-Y /Fgf5 go-Y we/wewal/wal homozygotes alopecia is observed seven days later, i. e., in 21-day-old animals. The progression of alopecia in triple homozygotes is expressed to a lesser degree than in double +/+we/wewal/wal homozygotes. A single dose of the Fgf5 go-Y gene also decreases the effect of interaction of the we and wal genes, but less than a double dose of this gene. The first signs of alopecia in mice of the +/Fgf5 go-Y we/wewal/wal genotype appear only three days later than in double +/+we/wewal/wal homozygotes. The data obtained demonstrate that the Fgf5 go-Y gene is a powerful modifier of mutant genes determining the process of alopecia. 相似文献
19.
The activity of citrate synthase (CS), a mitochondrial enzyme in the energy metabolism pathway, was studied in Euplotes focardii (Hypotrichia) and Uronema marinum (Scuticociliatia), isolated from samples of Antarctic seawater and, for comparison in E. vannus and U. nigricans , related ciliates from the Adriatic. The temperature-dependent characteristics of CS were investigated in the range 0–55°C, to evaluate mechanisms of thermal regulation, such as optimal temperature levels, activation energy, and kinetic parameters. CS activity was up to double that recorded in temperate organisms at reaction temperatures between 0 and 10°C. The optimal temperature for enzymatic activity was independent of T amb . Activation energy for CS was significantly lower in Antarctic ciliates than in temperate ones, indicating a significant increase in the reaction rate. K M at various temperatures of the reaction substrates indicated the higher affinity of CS for acetyl-CoA in both Antarctic organisms at lower temperatures. The data for thermal profiles for K M , showing greater differences between E. focardii and E. vannus than between U. marinum and U. nigricans , support the distinctive physiological characteristics of each species. E. focardii is an endemic and psychrophilic species, whereas U. marinum is a typically ubiquitous species, more adaptable to environmental changes. 相似文献
20.
Elaheh Sajadi Valiollah Babaipour Ali Asghar Deldar Bagher Yakhchali Seyed Safa-Ali Fatemi 《Biotechnology letters》2017,39(9):1395-1401