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农田土壤固碳措施的温室气体泄漏和净减排潜力   总被引:8,自引:0,他引:8  
逯非  王效科  韩冰  欧阳志云  郑华 《生态学报》2009,29(9):4993-5006
农田土壤固碳措施作为京都议定书认可的大气CO2减排途径受到了广泛关注.研究表明,农田土壤固碳措施在主要农业国家和全球都具有很大的固碳潜力.但是,实施农田土壤固碳措施有可能影响农业中化石燃料消耗和其他农业投入的CO2排放和非CO2温室气体排放.这些土壤碳库以外的温室气体排放变化可能抵消部分甚至全部土壤固碳效果,构成了农田土壤固碳措施的温室气体泄漏.因此,将土壤固碳和温室气体泄漏综合计算的净减排潜力成为了判定土壤固碳措施可行性的首要标准.综述总结了目前较受重视的一些农田措施(包括施用化学氮肥、免耕和保护性耕作、灌溉、秸秆还田、施用禽畜粪便以及污灌)的土壤固碳潜力,温室气体泄漏和净减排潜力研究成果.结果表明,温室气体泄漏可抵消以上措施土壤固碳效益的-241%~660%.建议在今后的研究中,应该关注土壤碳饱和、气候变化及土地利用变化对农田固碳措施温室气体泄漏和净减排潜力的评估结果的影响.  相似文献   
3.
Anoctamin-6 (Ano6, TMEM16F) belongs to a family of putative Ca2+-activated Cl channels and operates as membrane phospholipid scramblase. Deletion of Ano6 leads to reduced skeleton size, skeletal deformities, and mineralization defects in mice. However, it remains entirely unclear how a lack of Ano6 leads to a delay in bone mineralization by osteoblasts. The Na+/Ca2+ exchanger NCX1 was found to interact with Ano6 in a two-hybrid split-ubiquitin screen. Using human osteoblasts and osteoblasts from Ano6−/− and WT mice, we demonstrate that NCX1 requires Ano6 to efficiently translocate Ca2+ out of osteoblasts into the calcifying bone matrix. Ca2+-activated anion currents are missing in primary osteoblasts isolated from Ano6 null mice. Our findings demonstrate the importance of NCX1 for bone mineralization and explain why deletion of an ion channel leads to the observed mineralization defect: Ano6 Cl currents are probably required to operate as a Cl bypass channel, thereby compensating net Na+ charge movement by NCX1.  相似文献   
4.

Objective:

To evaluate the influence of elite-level alpine skiing on athletes’ skeleton.

Methods:

Thirteen professional alpine skiers (9 males and 4 females with mean age of 22.6 years) and their age- and height matched control subjects were measured with dual energy X-ray absorptiometry (total body, lumbar spine, proximal femur, forearm) and quantitative ultrasound (hand).

Results:

After adjusting for sex, age, weight and height, between-group differences were 15% (p=0.012) for the lumbar spine, 14% (p=0.022) for the femoral neck, 10% (p=0.051) for the total hip, and 11% (p=0.001) for the total body favoring the alpine skiers. However, after controlling for total body lean mass (~muscle mass), the group-differences lost their statistical significance, the borderline 10% difference (p=0.051) in femoral neck BMD excluded.

Conclusion:

Factors contributing to the alpine skiers’ higher BMD may not only include the greater muscle mass (~stronger muscles) of these athletes but also a large number of impacts and possibly other high-frequency features in external loading generated by the high-speed skiing performance.  相似文献   
5.
Although bone morphogenic protein (BMP) signaling promotes chondrogenesis, it is not clear whether BMP-induced chondrocyte maturation is cell-autonomously terminated. Loss of function of Smpd3 in mice results in an increase in mature hypertrophic chondrocytes. Here, we report that in chondrocytes the Runx2-dependent expression of Smpd3 was increased by BMP-2 stimulation. Neutral sphingomyelinase 2 (nSMase2), encoded by the Smpd3 gene, was detected both in prehypertrophic and hypertrophic chondrocytes of mouse embryo bone cartilage. An siRNA for Smpd3, as well as the nSMase inhibitor GW4869, significantly enhanced BMP-2-induced differentiation and maturation of chondrocytes. Conversely, overexpression of Smpd3 or C2-ceramide, which mimics the function of nSMase2, inhibited chondrogenesis. Upon induction of Smpd3 siRNA or GW4869, phosphorylation of both Akt and S6 proteins was increased. The accelerated chondrogenesis induced by Smpd3 silencing was negated by application of the Akt inhibitor MK2206 or the mammalian target of rapamycin inhibitor rapamycin. Importantly, in mouse bone culture, GW4869 treatment significantly promoted BMP-2-induced hypertrophic maturation and calcification of chondrocytes, which subsequently was eliminated by C2-ceramide. Smpd3 knockdown decreased the apoptosis of terminally matured ATDC5 chondrocytes, probably as a result of decreased ceramide production. In addition, we found that expression of hyaluronan synthase 2 (Has2) was elevated by a loss of Smpd3, which was restored by MK2206. Indeed, expression of Has2 protein decreased in nSMase2-positive hypertrophic chondrocytes in the bones of mouse embryos. Our data suggest that the Smpd3/nSMase2-ceramide-Akt signaling axis negatively regulates BMP-induced chondrocyte maturation and Has2 expression to control the rate of endochondral ossification as a negative feedback mechanism.  相似文献   
6.
目的:研究甲亢低骨量患者131I治疗后干预治疗的效果。方法:对100例甲亢低骨量患者,随机分为两组:A组50例,131I治疗后口服钙尔奇D及罗盖全治疗;B组50例,131I治疗后骨质自然恢复。另设C组50例为正常对照组。于131I治疗前、治疗后3、6及12个月测定A、B两组骨密度(BMD),观察其骨质变化并评价治疗效果。结果:(1)A组随治疗时间延长BMD逐渐升高,具有一定的规律性,腰椎(L2-4)骨密度3个月提高明显(t=-2.111,P=0.04)且12个月时达到与C组无统计学差异(t=-2.290,P=0.202)。(2)B组3个月时腰椎BMD有所降低,12个月时升高明显(股骨颈t=-2.327,P=0.043;腰椎(L2-4)t=-2.798,P=0.000)。(3)6个月时两组腰椎骨密度改善幅度出现统计学差异(t=-2.416,P=0.018),12个月时差异显著(t=-3.259,P=0.002)。结论:131I联合钙尔奇D与罗盖全治疗甲亢低骨量患者,其恢复时间及疗效均用131I治疗,能有效防止骨量的进一步下降及减少骨质疏松症的发生。  相似文献   
7.
骨髓基质干细胞(Bone marrow stromal cells,BMSCs)是一种具有组织修复和免疫调节功能的多能干细胞,它主要存在于骨髓中,然而,如今我们发现,在其他的一些组织中也存在它的身影,例如:脂肪组织、肌肉组织和肌腱组织等。通过骨髓穿刺的方法可以很容易的获得骨髓基质干细胞,它在体外有很强的增殖能力,即使没有动物血清和人工生长因子也可以用进行细胞培养。缺血性骨坏死可以由很多病因引起,研究发现,自身免疫性疾病和血液系统疾病治疗应用的激素与缺血性骨坏死的发生具有很大的相关性,但是,激素的应用在一些严重的疾病中往往又是不可避免的,这就需要我们找到一种方法来预防和治疗激素相关缺血性骨坏死。现在,治疗缺血性骨坏死的标准方法是髓芯减压术,但到了疾病晚期的时候,髓芯减压术治疗的效果就已经微乎其微了,由于骨髓基质干细胞所具有的分化潜能、易于获得和增殖的能力,使它可能成为治疗缺血性骨坏死的一种潜在的补充方式。  相似文献   
8.
肝硬化是一种临床常见的肝病良性终末期表现。目前临床上尚缺乏有效的治疗措施。肝脏移植是最理想的治疗方法,但受供体肝脏来源限制,且费用昂贵。近年来开展的自体骨髓干细胞(BMSCs)移植治疗,为肝硬化的治疗带来了新的希望。BMSCs主要包括造型血干细胞和间充质干细胞,其具有可塑性,体外通过生长因子,体内利用特定微环境均可诱导BMSCs分化为肝前体细胞和成熟肝细胞,并明显改善肝功能。从动物实验到临床研究亦表明,BMSCs具有来源丰富、费用低廉、损伤小、自体移植不栓塞、无排斥反应等优点,为治疗肝病带来了新思路,有望成为生物人工肝的细胞来源。本文就BMSCs移植治疗肝硬化的研究现状,尤其是移植途径以及在肝脏内定居、迁移和分化机制的示踪观察方法和存在的问题作一综述,以期为从事肝病研究的同仁提供参考依据。通过对BMSCs移植从基础研究及临床应用的最新进展的描述,展示BMSCs在肝硬化治疗方面良好的治疗前景。  相似文献   
9.
Polyphenol have been reported to have physiological effects with respect to alleviating diseases such as osteoporosis and osteopetrosis. We recently reported that the olive polyphenol hydroxytyrosol accelerates bone formation both in vivo and in vitro. The present study was designed to evaluate the in vivo and in vitro effects of apigenin (4′,5,7-trihydroxyflavone), one of the major polyphenols in olives and parsley, on bone formation by using cultured osteoblasts and osteoclasts and ovariectomized (OVX) mice, respectively. Apigenin markedly inhibited cell proliferation and indices of osteoblast differentiation, such as collagen production, alkaline phosphatase activity, and calcium deposition in osteoblastic MC3T3-E1 cells at concentrations of 1–10 μM. At 10 μM, apigenin completely inhibited the formation of multinucleated osteoclasts from mouse splenic cells. Moreover, injection of apigenin at 10 mg kg−1 body weight significantly suppressed trabecular bone loss in the femurs of OVX mice. Our findings indicate that apigenin may have critical effects on bone maintenance in vivo.  相似文献   
10.
The leakage of various inorganic carbon species from air-grown cells of Synechococcus UTEX 625 was investigated after a light to dark transition or during a light period using a mass spectrometer under a wide variety of experimental conditions. Total inorganic carbon efflux and CO2 efflux during the initial period of darkness were measured with or without carbonic anhydrase in the reaction medium respectively. The HCO3? efflux after a light to dark transition was estimated by difference. Carbon dioxide efflux in the light was measured by inhibiting CO2 transport with either Na2S or COS3 or quenching the 13C inorganic carbon transport by the addition of 12C inorganic carbon in excess. In cells in which CO2 fixation was inhibited, when only the HCO3? transport system was fully operative, CO2 effluxed continuously during the light period at a rate equal to about 25% of that in darkness. When only the CO2 transport system was operative, HCO3? effluxed during the light period. The difference between the light and dark efflux rates was consistent with a 0.6 unit decrease in the intracellular pH upon darkening the cells. The permeabilities of the cell for CO2 (2.94 ± 0.14 ± 10?8ms?1; mean ± SE, n=137) and HCO3? (1.4–1.7 ± 10?9 ms?1) were calculated.  相似文献   
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