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1.
Yang XG  Li Y  Dai SW  Liu ZJ  Wang WF 《应用生态学报》2011,22(12):3177-3188
Based on the 1961-2007 ground surface meteorological data from 558 meteorological stations in China, this paper analyzed the differences of agricultural climate resources in China different regions, and compared the change characteristics of the agricultural climate resources in 1961-1980 (period I) and 1981-2007 (period II), taking the year 1981 as the time node. As compared with period I, the mean annual temperature in China in period II increased by 0.6 degrees C, and the > or = 0 degrees C active accumulated temperature in the growth periods of chimonophilous crops and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased averagely by 123.3 degrees C x d and 125.9 degrees C x d, respectively. In 1961-2007, the mean annual temperature increased most in Northeast China, and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased most in South China. The whole year sunshine hours and the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops in period II decreased by 125.7 h, 32.2 h, and 53.6 h, respectively, compared with those in period I. In 1961-2007, the annual sunshine hours decreased most in the middle and lower reaches of Yangtze River, while the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops decreased most in North China and South China, respectively. In the whole year and in the growth periods of chimonophilous and thermophilic crops, both the precipitation and the reference crop evapotranspiration in this country all showed a decreasing trend, with the largest decrement in the precipitation in the whole year and in the growth periods of chimonophilous and thermophilic crops in North China, the largest decrement in the reference crop evapotranspiration in the whole year and in the growth periods of thermophilic crops in the middle and lower reaches of Yangtze River, and the largest decrement in the reference crop evapotranspiration in the growth periods of chimonophilous crops in Northwest China. In 1961-2007, the climate in China in the whole year and in the growth periods of thermophilic crops showed an overall tendency of warm and dry, and the climate in the growth periods of thermophilic crops became warm and dry in Southwest China, North China, and Northeast China, but warm and wet in the middle and lower reaches of Yangtze River, Northwest China, and South China, whereas the climate in the growth periods of chimonophilous crops became warm and dry in North China, but became warm and wet in Northwest China.  相似文献   

2.
利用中国558个气象台站1961-2007年地面气象观测资料,分析了不同区域农业气候资源变化的差异,并分析和比较了1961-1980年(时段Ⅰ)和1981-2007年(时段Ⅱ)的农业气候资源变化特征.结果表明: 与时段Ⅰ相比,时段Ⅱ中国年均气温增加了0.6 ℃,喜凉作物生长期内≥0 ℃积温和喜温作物生长期内≥10 ℃积温分别平均增加123.3和125.9℃·d;1961-2007年,年均气温增幅最大的区域是东北地区,喜温作物生长期内≥10 ℃积温增幅最大的是华南地区.对全国而言,与时段Ⅰ相比,时段Ⅱ在全年、喜凉和喜温作物生长期内日照时数分别减少了125.7、32.2和53.6 h;1961-2007年,长江中下游地区年日照时数的减幅最多,喜凉和喜温作物生长期内日照时数减少量最大的地区分别是华北和华南地区;在全年、喜凉和喜温作物生长期内,中国的降水量和参考作物蒸散量总体均表现为减少趋势,其中,华北地区在全年、喜凉和喜温作物生长期内降水量的减幅均最大,长江中下游地区参考作物蒸散量在全年和喜温作物生长期内的减幅最大,西北地区参考作物蒸散量在喜凉作物生长期内的减幅最大.研究期间,中国气候在全年和喜温作物生长期内总体表现为暖干趋势,其中,喜温作物生长期内西南、华北和东北地区为暖干趋势,长江中下游、西北和华南地区为暖湿趋势,喜凉作物生长期内华北地区为暖干趋势,西北地区为暖湿趋势.  相似文献   

3.
There is currently great interest shown in understanding the process of embryogenesis and, due to the relative inaccessibility of these structures in planta, extended studies are carried out in various in vitro systems. The culture of isolated zygotes in particular provides an excellent platform to study the process of in planta embryogenesis. However, very few comparisons have been made between zygotic embryos grown entirely in cultures and those grown in vivo. The present study analyses the differences and similarities between the in vitro and in vivo development of wheat zygotic embryos at the level of morphology and histology. The study was possible thanks to an efficient culture system and an appropriate method of preparing isolated wheat zygotes for microscopy. The in vitro embryos were fixed, embedded and sectioned in the two-celled, globular, club-shaped and fully differentiated stages. Embryos developing in vitro closely followed the morphology of their in planta counterparts and their cell types and tissues were also similar, demonstrating the applicability of the present culture system for studying the process of zygotic embryogenesis. However, some important differences were also detected in the case of in vitro development: the disturbance of or lack of initial polarity led to changes in the division symmetry of the zygotes and subsequently to the formation of uniform cells in the globular structures. Presumably, differences between the in vitro and in planta environments resulted in a lower level of differentiation and maturation in in vitro embryos and in abundant starch and protein accumulation in the scutellum.  相似文献   

4.
c-fos和c-myc在北方山溪鲵精子发生中的表达   总被引:1,自引:0,他引:1  
用免疫组织化学方法检测原癌基因cf-os和c-myc蛋白在北方山溪鲵(Batrachuperus tibetanus)精子发生中的表达定位。结果显示,在精原细胞缓慢增殖期,8、9月,FOS阳性反应物出现在精原细胞的胞质及核膜外,10、11月,FOS在少量精原细胞的胞核中表达。在精原细胞快速增殖期,即翌年4月,FOS定位在精原细胞的胞质中;5月,FOS在大量的胞核中强阳性表达;6月,FOS定位于部分精母细胞核质和核膜下;7月,FOS在一些精子细胞的核质和核膜下表达。MYC在8、9月的部分精原细胞胞质中表达较弱,在101、1月阳性反应出现在个别精原细胞的核质中。翌年4月,MYC在精原细胞核周围的胞质中表达;5月在大量的精原细胞核膜下有强表达;6月,MYC在一些精母细胞核膜下表达;7月,MYC在部分精子细胞的核膜下弱表达。结果表明,北方山溪鲵的原癌基因cf-os和c-myc表达大强度在生精细胞发育中呈阶段性,表达的强度和细胞数量与细胞增殖的速度相一致。FOS和MYC在精原细胞内从胞质向胞核的转移与细胞快速增殖的时期相吻合。说明cf-os和c-myc对精原细胞有丝分裂有促进作用,并参与精母细胞成熟分裂的调控。  相似文献   

5.
Insulin-like growth factors (IGF-I and -II) are present in the brain during development, with high levels of both being also found in the periphery particularly in the embryo. IGFs in the brain are believed to stimulate the proliferation of neuronal and glial precursors and their phenotypic differentiation. Using in situ hybridization, we have investigated the distribution of cells producing IGF-I and -II in the rat fetus during the second half of prenatal development with special emphasis on the peripheral and central nervous system. High levels of IGF-I mRNA were found in the olfactory bulb and in discrete neurons of the cranial sensory ganglia, notably in the trigeminal ganglion, as early as 13 days of gestation, in the pineal primordium of 18 day old fetuses, and in discrete groups of cells in the cochlear epithelium located laterally outside the forming spiral organ, in day 13 to 21 fetuses. High levels of IGF-II mRNA in the brain, besides the choroid plexus and the leptomeninges, were detected in hypothalamus, in the floor of the 3rd ventricle at all stages studied, in the pineal primordium at 18 days and in the pars intermedia of the pituitary or in the Rathke's pouch epithelium from which it is derived, with progressive fading towards the end of the gestation. In the peripheral nervous system the IGF-II mRNA was only found in association with the vascular endothelia of the ganglia. IGF-II mRNA in the nervous system was found in highly vascularized areas, meninges, blood vessels and choroid plexuses. It is thus associated with structures involved in the production of extracellular fluids and/or substrate transport and supply in the nervous tissues. A more specific role in the differentiation or fetal endocrine function should be considered for IGF-II in cells producing melatonin and melanocyte stimulating hormone (MSH) in the pineal and pituitary glands, respectively. The presence of IGF-I mRNA in the nervous system could be associated with fiber outgrowth and synaptogenesis in the cases of olfactory bulb and developing iris. The role of IGF-I in restricted populations of cells of the cochlear epithelium and in the pineal gland is unclear and requires further investigations including a search for IGF-I receptors in possible target cells. In the sensory ganglia, the presence of high levels of IGF-I mRNA eventually corresponds to the production, by post-translational processing, of the amino-terminal tripeptide of IGF-I, which might represent a neurotransmitter for these sensory neurons.  相似文献   

6.
Studies have been made on the content and distribution of Cd, K, Mg, Ca, S and P in organs and cells of mussels and scallops before and after immersion in water containing cadmium chloride. In normal molluscs, the lowest content of Cd was found in the gonads; cadmium content of the hepatopancreas and kidney in the scallop is correspondingly 20 and 40 times higher than in the mussel. After immersion in water with cadmium (250 micrograms/l in summer experiments and 500 micrograms/l in spring ones), cadmium content of the hepatopancreas and kidney of the scallop was found to be also higher than that in the mussel, although the difference is less significant, being dependent on the season of year. The highest accumulation of cadmium (9.760 +/- 790 micrograms/g dry weight) was observed in the scallop kidney in summer period. After immersion in cadmium-containing water, the content of sulphur in the kidney and hepatopancreas increases, positive correlation being observed between the distribution of Cd and S. Exposure to cadmium results in the increase of Ca and Mg content in the gonads of scallops, as well as in the increase in Ca content of the gonads of mussels. Accumulation of cadmium in the gonads is rather small, maximum density of the material being observed histochemically in the gonadal wall. Morphological changes in the gonadal cells of mussels in summer period may be associated with the increase in cellular calcium.  相似文献   

7.
Depths of thermocline and the redox zone, concentrations of dissolved and suspended carbon, and nitrogen and phosphorus in seston were measured in the pelagial of the saline meromictic Lake Shira (southern Siberia) in different years (2007–2011); the relationship of the values for those parameters with air-temperature variations was assessed. Positive correlations between both air temperatures in the previous year and the depth of the redox zone in winter and air temperature in April and the thermocline depth in summer were revealed. In the mixolimnion, the ratio of total nitrogen to total phosphorus almost always exceeded the Redfield ratio (16: 1); seston deficiency both in nitrogen and phosphorus was monitored in different seasons and at various depths. The amount of seston in the mixolimnion in summer almost doubled the amount of seston in winter and was directly related with the depth of the thermocline. In the monimolimnion, seston was rich in nitrogen and phosphorus. The amount of seston in the monimolimnion varied in different years and depended both on the air temperature in the previous year and the size of the zone.  相似文献   

8.
利用合成分析和秩相关系数2种方法,分析了河北2种生态类型蝗区中夏蝗LocustamigratoriaL.发生程度与气象条件的关系,以确定影响夏蝗大发生的关键气象因子。结果表明:2个类型蝗区大发生年以前一年5月至当年夏蝗出土以前的气温偏高、降水偏少为主;前一年6月下旬、7月上旬、8月上旬、8月中旬气温、6月上旬降水、当年3月下旬降水、4月下旬气温为沿海蝗区关键影响因子,前一年7月上旬和8月下旬气温、5月中旬降水及当年2月中、下旬气温、4月下旬和5月上旬气温为洼淀蝗区的关键影响因子。  相似文献   

9.
The effects of alternating magnetic field (AMF) with the frequency of 50 Hz on the dynamics of unfolding of cotyledon leaves, the composition and level of polar and neutral lipids and their component fatty acids (FA) were studied in 5-day-old radish seedlings (Raphanus sativus L. var. radicula D.L., cv. Rozovo-krasnyi s belym konchikom) grown in the light and in the dark. AMF weakened the inhibitory effect of light on unfolding of cotyledon leaves. In the light, the total content of lipids, as well as the level of polar and neutral lipids, in the seedlings in AMF was greater than in control material. In polar lipids, the total amount of glyco-and phospholipids increased; in neutral lipids, the level of triacylglycerols rose. The ratio between phospholipids and sterols (PhL/S) increased. In the dark, the total content of lipids and the level of neutral lipids in the seedlings in AMF were lower than in control material, and the ratio PhL/S decreased. In control material, there were no differences in the relative total content of unsaturated FA in the light and in the dark, whereas the level of linolenic acid was higher in the light than in the dark. AMF induced a decrease in the content of linolenic acid in the light and a rise in the dark; the level of erucic acid in the light decreased. The ratio between unsaturated and saturated FA decreased both in the light and in the dark. It was concluded that AMF with the frequency of 50 Hz was an adjusting agent considerably changing the content of lipids in the radish seedlings in the light and in the dark.  相似文献   

10.
EEG and EPs in the visual and parietal neocortical areas and the hippocampus were studied in freely behaving rats at the age of two-three months after antenatal hypoxia. Increase of spectral power in delta and theta bands and its decrease in alpha and beta bands in the background EEG and in responses to a protracted light stimulation were observed in experimental animals in comparison to control ones. The most pronounced changes were observed in the parietal cortex and hippocampus. The character of changes in latencies and the share of individual EP components recorded point to an accelerated excitation reverberation in neuronal networks in response to afferent stimuli and to a prolongation of after-discharges in the parietal cortex and hippocampus testifying to peculiarity of information processing in these brain structures. On the basis of other authors' data, certain parallelism is supposed to exist between the electrophysiological parameters in experimental animals and some groups of children with mental retardation.  相似文献   

11.
The roles of corticotropin and morphine in the regulation of phosphofructokinase (PFK) activity in rat mammary glands were investigated by the administration of corticotropin, morphine and dexamethasone. Corticotropin increased the activity of PFK in the mammary glands of intact and hypophysectomised animals but was without any effect in tissues from ovariectomised and adrenalectomised animals. Morphine administration resulted in a significant decrease in the enzyme's activity in intact animals only. A combined dose of corticotropin and morphine significantly reduced the corticotropin-induced increase in the activity in both intact and hypophysectomised animals. Dexamethasone treatment resulted in a significant increase in the activity in hypophysectomised and ovariectomised plus adrenalectomised animals and morphine was able to reduce the glucocorticoid-induced rise. It is postulated that endogenous opioids might be playing a dual role in the regulation of glycolysis by inhibiting the release of corticotropin and regulating the action of glucocorticoids at the cellular level in the mammary gland.  相似文献   

12.
微观辨证学之研究:气血辨证与细胞化学含量的关系   总被引:2,自引:0,他引:2  
在临床上为揭示肝脏病肝纤维化气虚血瘀和气滞血瘀病者,对细胞化学含量的变化,运用显微分光光度技术分析,结果发现气虚血瘀者单核细胞ANAE、ACP,红细胞LDH和嗜中性粒细胞ADP明显降低,气滞血瘀者单核细胞ANAE、红细胞LDH及嗜中性粒细胞ADP较正常组偏低,但却较气虚血瘀组为高,单核细胞ACP高于气虚血瘀组和正常对照组.据此,可将气虚、气滞血瘀及正常对照3组区别开来.  相似文献   

13.
14.
P Ernfors  C Wetmore  L Olson  H Persson 《Neuron》1990,5(4):511-526
Cells expressing mRNA for hippocampus-derived neurotrophic factor (HDNF/NT-3) or brain-derived neurotrophic factor (BDNF) were identified by in situ hybridization. In the rat brain, HDNF mRNA was predominantly found in pyramidal neurons in CA1 and CA2 of the hippocampus. Lower levels of HDNF mRNA were found in granular neurons of the dentate gyrus and in neurons of the taenia tecta and induseum griseum. BDNF mRNA-expressing cells were more widely distributed in the rat brain, with high levels in neurons of CA2, CA3, and the hilar region of the dentate gyrus, in the external and internal pyramidal layers of the cerebral cortex, in the claustrum, and in one brainstem structure. Lower levels were seen in CA1 and in the granular layer of the hippocampus, in the taenia tecta, and in the mammillary complex. In peripheral tissues, HDNF mRNA was found in glomerular cells in the kidney, secretory cells in the male rat submandibular gland, and epithelial cells in secondary and tertiary follicles in the ovary. Cells expressing BDNF mRNA were found in the dorsal root ganglia, where neurons of various sizes were labeled.  相似文献   

15.
Comparative investigations of somatotropin and prolactin contents in the fluid of antral follicles and blood serum of cows in different phases of the oestrous cycle were performed. The somatotropin concentration in the fluid was shown to rise with increasing the follicle diameters from 3-5 to 6-10 mm in the follicular phase and to decrease in follicles of diameter 11-20 mm in the luteal phase. The prolactin concentration was higher in the fluid of follicles 11-20 mm in diameter than in those of 3-5 mm in diameter in the follicular phase and did not depend on the follicle size in the luteal phase. Concurrently, the prolactin content in follicles 3-5 mm in diameter was higher in the luteal than follicular phase of the cycle. As compared to the follicular phase, an increase in the prolactin concentration in the bovine blood serum during the luteal phase was also found. The data obtained indicate that changes in the somatotropin and prolactin contents in the follicular fluid are related to processes regulating growth and development of antral follicles depending on the phase of oestrous cycle and to changes in the blood hormone concentrations as well.  相似文献   

16.
S F Amakiri 《Acta anatomica》1979,103(4):434-444
Various histochemical and histological techniques were used to study the melanin and dopa-positive cell distribution in the skin of some tropical and temperate breeds of cattle in Nigeria. Melanin pigments were concentrated in the basal and lower spinous layers of the epidermis and in the hair cortex, follicle sheaths and papillae of the various breeds. In the White Fulani and N'Dama breeds, melanin pigments were however found in all layers of the epidermis. Dopa-positive cells (melanocytes) were observed in the epidermis, dermis and hair follicles; the distribution pattern varied among breeds, being copiously disposed in the basal epidermis and papillary dermis in the White Fulani and Muturu and, except in areas of thick epidermal ridges, scanty in the epidermis and dermis of the Friesian and N'Dama. Mast cell distribution pattern in the various breeds was similar to that of the dopa-positive cells. Peroxidase-positive cells were present in the basal epidermis and upper dermis of the Muturu, widespread in the subepidermal layer of the N'Dama and very scanty in the dermis of the White Fulani and Friesian. Acid phosphatase activity was intense in the granular layer of the Muturu and N'Dama breeds and also in the papillary dermis and hair follicles, whereas alkaline phosphatase-positive dendritic cells, and 'clear' cells were also observed in the basal and upper epidermis.  相似文献   

17.
By means of the indirect immunoperoxidase method in deparaffinized slices a comparative investigation on distribution of the female milk lactoferrin (LF) in tissues of the mature person and in the fetus has been performed. LF is revealed in cells of the neutrophil line of the mature person and of the fetus and in the secretory epithelium of some organs of the mature person (in the mammary, submandibular and parotid salivary glands, in the bronchial mucous membrane glands in the fundal and pyloric glands of the stomach). In all the cases investigated LF is revealed in the cells producing serous secrete: in the cells of the serous terminal parts and in the serous semilunar mixed terminal parts of the salivary glands, in the serous cells of the bronchial glands and in the chief cells of the gastric mucous membrane glands. In the fetal secretory epithelium of the organs LF is not found. As LF is revealed in the secretory epithelium of the mature person and is not revealed in the corresponding epithelium of the fetus, it should be considered as a marker of the cells, that reach certain degree of differentiation.  相似文献   

18.
在三月红荔枝(Litchi chinensis cv.Sanyuehong)果实膨大期对树冠喷施0.2%磷酸二氢钾(KP)水溶液,以探讨磷酸二氢钾对荔枝果实贮藏性的影响。结果表明:(1) KP处理的果实在贮藏期前17d,失重率及果肉可溶性固形物、酸、VitC、花色素苷等指标的变化趋势与对照基本相似;(2) KP处理的果肉可溶性蛋白质含量变化与对照有明显差异,而果皮的可溶性蛋白质含量在贮藏期前10d变化动态与对照一致,此后呈相反的变化趋势;(3)果皮POD活性显著高于果肉,KP处理和对照的果肉POD活性在贮藏第3d后、果皮POD活性在第17d前分别具有相似变化趋势;(4)果肉中CAT活性在贮藏第3~17d期间都显著或极显著高于果皮,KP处理和对照果肉、果皮CAT活性动态变化均为单峰曲线。  相似文献   

19.
Heme oxygenase activity, the level of spontaneous and ascorbat-induced LPO in the liver, kidney and spleen homogenates of rats and blood serum absorption spectrum in the Soret region in different periods both after CdCl2 and prior alpha-tocopherol administration were studied. The increase in the hemolysis products content in the serum was observed in 15 min after CdCl2 injection and remained during 24 h. Heme oxygenase activity in the liver and kidney increased after 6 h and stayed at the same level 24 h after CdCl2 administration. The level of spontaneous LPO in the spleen increased after 6 h, and in the liver and kidney the level of spontaneous and ascorbat-induced LPO increased in 24 h after CdCl2 injection. The preliminary alpha-tocopherol administration did not prevent the accumulation of hemolysis products in the serum and the increase of heme oxygenase activity in the liver and kidney caused by CdCl2 administration. However, the increase in the ascorbat-induced LPO in these organs was completely blocked. The role of heme and LPO in the heme oxygenase induction by CdCl2 are discussed.  相似文献   

20.
The uptake of nutrients and activities of membrane enzymes in the kidney were investigated using renal brush border membrane (BBM) vesicles in acute pyelonephritis in rats. A significant decrease (P less than 0.001) in the uptake of D-glucose and L-phenylalanine was observed in both the unobstructed right and obstructed left kidney, while there was a significant increase (P less than 0.001) in the uptake of L-alanine in the left kidney of pyelonephritic rats, demonstrating disturbances in the reabsorption of the glucose and aminoacids in the kidneys. Vmax of alkaline phosphatase, leucine-amino-peptidase and maltase was found to be decreased in the left kidney, suggesting that there was a reduction in the active enzyme molecule number. Km of alkaline phosphatase and leucine-aminopeptidase remained unchanged, while km of maltase decreased in both the right and left kidneys. An increase in the Vmax of alkaline phosphatase and leucine-aminopeptidase and substrate affinity of the maltase in the right kidney demonstrated a compensatory phenomenon for the malfunctioning of the left kidney. This is the first report demonstrating alterations in reabsorption of nutrients and BBM enzymes in experimental pyelonephritis.  相似文献   

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