不同含水量的豌豆种子萌发时物质动员及代谢研究

不同含水量的豌豆种子在饱和水蒸气中保持 7d过程中 ,含水量低于萌动临界含水量时 ,子叶中贮藏蛋白质和淀粉的动员不能启动 ;含水量达到或超过萌动临界含水量 ,贮藏物质的动员被启动。豌豆种子萌动后 ,子叶中蛋白质和淀粉的动员程度与种子含水量呈正相关 ;前 3 d物质动员的程度比后 4 d强烈得多。因此 ,含水量是豌豆种子萌发时物质动员的启动因子和调节因子。同时 。

氮素营养对小麦干物质积累与转运的影响

在大田条件下,以冬小麦"长旱58"为供试材料,研究不同氮肥用量对小麦干物质转运、积累和分配的影响,共设5个氮水平,即N1(0kg/hm2)、N2(80kg/hm2)、N3(150kg/hm2)、N4(195kg/hm2)、N5(300kg/hm2)。结果表明:在氮肥用量为195kg/hm2的水平下,籽粒获得最高产量,N1处理产量最低。其余茎中干物质对籽粒贡献率最大,而颖壳是灌浆期干物质转运最先发生的部位。N4处理下花后干物质积累最大,而花前同化物转运率最小,N1和N2处理花前同化物对籽粒的贡献率最大,N5处理花后干物质积累小于N4,说明合理的增施氮肥可增加灌浆期光合同化物积累,从而提高产量。

社会动员的变迁及内在机制——以公益献血的动员研究为例

自1998年实行无偿献血制度以来,中国公益献血事业取得了长足的进步,以往学界往往将这种进步归因于社会体制、政府管理能力、组织结构或者献血者素质的变化,这些解释一定程度上说明了中国献血事业的特色和经验,但其视角却局限于过"大"、"偏"和"弊"。社会动员机制也可以作为公益献血事业进步的一个解释维度。针对献血的社会动员经历了政治动员、物质动员和主体动员的阶段性过渡和有效衔接;在献血动员变迁的过程中伴随着动员意义的建构。公益献血进步的探讨,不仅能反观社会动员的变迁,而且管窥了社会动员变迁背后的社会转型。

20世纪90年代以来国内政治动员问题研究述评

通过对20世纪90年代以来国内政治动员问题的研究的分析,从侧重于军事目的和政治目的两个角度归纳了政治动员的概念研究;阐明了关于政治动员的分类、具体方式和功能方面的研究;并对如何提高政治动员的有效性问题进行了综述。最后指出了20世纪90年代以来政治动员问题研究的不足。

绿色器官衰老进程中营养物质的动员与再利用研究进展

绿色器官的衰老是植株生长发育的一个内在组成部分,其重要的生物学意义在于营养物质的动员与再利用。作为最重要的营养"源"器官,衰老叶片中发生大规模的降解代谢活动,由此产生的大量小分子物质,包括糖类,氨基酸,核苷酸和可再生利用的矿质元素等会通过筛管转运至新生的组织器官,即"库"器官,特别是种子中,为其快速生长发育提供充足的营养供应。本文主要介绍了绿色器官衰老过程中氮素的营养动员与再利用研究进展,包括叶片中蛋白的降解和氨基酸的代谢转化,以及筛管装载和卸载。最后,对未来的研究方向进行了展望,提出了作物叶片光合总量和营养物质利用效率双双趋于最大化的理想叶片衰老模式。

Bone mineral density in lifelong trained male football players compared with young and elderly untrained men

Purpose: The purpose of the present controlled cross-sectional study was to investigate proximal femur and whole-body bone mineral density(BMD), as well as bone turnover profile, in lifelong trained elderly male football players and young elite football players compared with untrained age-matched men.Methods: One hundred and forty healthy, non-smoking men participated in the study, including lifelong trained football players(FTE, n = 35)aged 65—80 years, elite football players(FTY, n = 35) aged 18—30 years, as well as untrained age-matched elderly(UE, n = 35) and young(UY,n = 35) men. All participants underwent a regional dual-energy X-ray Absorptiometry(DXA) scan of the proximal femur and a whole-body DXA scan to determine BMD. From a resting blood sample, the bone turnover markers(BTMs) osteocalcin, carboxy-terminal type-1 collagen crosslinks(CTX-1), procollagen type-1 amino-terminal propeptide(P1NP), and sclerostin were measured.Results: FTE had 7.3%—12.9% higher(p < 0.05) BMD of the femoral neck, wards, shaft, and total proximal femur in both legs compared to UE,and 9.3%—9.7% higher(p < 0.05) BMD in femoral trochanter in both legs compared to UY. FTY had 24.3%—37.4% higher(p < 0.001) BMD in all femoral regions and total proximal femur in both legs compared to UY. The whole-body DXA scan confirmed these results, with FTE showing similar whole-body BMD and 7.9% higher(p < 0.05) leg BMD compared to UY, and with FTY having 9.6% higher(p < 0.001) wholebody BMD and 18.2% higher(p < 0.001) leg BMD compared to UY. The plasma concentration of osteocalcin, CTX-1, and P1NP were 29%,53%, and 52% higher(p < 0.01), respectively, in FTY compared to UY.Conclusion: BMD of the proximal femur and whole-body BMD are markedly higher in lifelong trained male football players aged 65—80 years and young elite football players aged 18—30 years compared to age-matched untrained men. Elderly football players even show higher BMD in femoral trochanter and leg BMD than untrained young despite an age difference of 47 years.