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QUANTITATIVE THEORY AND THE CONTROL OF SOIL FERTILITY 总被引:1,自引:1,他引:0
D. J. GREENWOOD 《The New phytologist》1983,94(1):1-18
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不同水肥条件对春玉米光合运转关系的影响及其产量效应的研究 总被引:2,自引:0,他引:2
以两种土壤水分和4种土壤肥力水平对春玉米光合运转关系的影响及其产量效应进行了较深入的探讨。在土壤水分适宜条件下,不同土壤肥力春玉米叶片光合速率随肥力水平的提高而增加的主要原因是气孔因素的限制,光合速率与籽粒产量呈现极显著正相关关系。 相似文献
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广西宜山县不同林型人工林凋落物与土壤肥力的研究 总被引:24,自引:2,他引:22
根据1984—1989年的定位观测,广四宜山县庆远林场27—32龄马尾松纯林、23—28龄柠檬桉与马尾松混交林和40—45龄麻栎林的年平均凋落物总量分别为548.3、511.8和479.5g/m~2。通过凋落物归还土壤的营养元素(N、P、K、Ca、Mg、Mn、Cu、Zn)总量依次为0.59278、0.78789和1.14750g/m~2·a。土壤肥力测试表明,桉松混交林和麻栎林的土壤旱季含水量、孔隙度、养分含量、微生物数量及呼吸作用强度均高于马尾松纯林。 相似文献
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The chemical composition of perinuclear crystals of Lychnis chalcedonica and intranuclear crystals of Dianthus barbatus in leaf tissue embedded in glycol methacrylate was tested by differential enzyme digestion of ultra-thin sections. The Lychnis crystals were digested readily by pepsin but with great difficulty and never to completion by trypsin. The Dianthus crystals were rapidly and completely digested by pronase; inconsistently and with difficulty by pepsin; and were unaffected by trypsin. Pre-incubation with water increased the effectiveness of pepsin digestion. Neither RNase nor DNase had any effect, either alone, or when preceded or followed by the proteinases. It was concluded that the Lychnis crystals are composed of protein that is probably high in aromatic amino acid content, and possibly low in the basic amino acids arginine and lysine. The Dianthus crystals also seem to be protein, but because of their amino acid composition or conformation, and possibly because of complex reactions with the fixative, these crystals are not readily hydrolyzed by pepsin and trypsin. 相似文献
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银杏叶提取物对高脂血症调脂机制的新探 总被引:14,自引:1,他引:13
目的 :通过观察银杏叶提取物对高脂血症病人调脂过程中肠道菌群的变化来探讨其调脂机制。方法 :对于 2 2名高脂血症患者给予银杏叶提取物 9片 / d,治疗 4w,检测其治疗前后空腹血脂变化 ,及高脂血症组治疗前与正常人肠道菌群变化 ,和高脂血症组治疗前后肠道菌群变化。结果 :(1)高脂血症患者经银杏叶提取物治疗后 TC、TG、L DL-C较治疗前均明显降低 (P<0 .0 5)。 (2 )高脂血症患者银杏叶提取物治疗前较正常人肠道菌群变化显著 (P<0 .0 1)。高脂血症组银杏叶治疗后较治疗前肠道菌群变化显著 (P<0 .0 1)。结论 :(1)银杏叶提取物降脂有显著疗效。 (2 )脂质代谢紊乱时肠道菌群较正常人明显变化 (P<0 .0 1) ,尤其双歧杆菌、乳杆菌等明显减少 ,而治疗后肠道菌群得到调整 ,说明银杏叶可能通过扶植肠道有益菌生长繁殖 ,如双歧杆菌、乳杆菌等对脂质代谢发挥作用 ,达到其调脂目的 相似文献
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采用原位(In situ)模拟实验方法研究了外加N源对杉木叶凋落物分解及土壤养分淋失的影响,结果表明,施加NH^+4-N时,杉木叶凋落物的失重率与对照(未加任何N的处理)相比,没有差异:而施加NO^-1-N时,使杉木叶凋落物分解速率显著提高(p=0.05,达10%以上,与施加NH^+4-N相比,施加NO^-3-N明显促进了杉木叶凋落物的分解(p=0.05)。施加NH^+4-N和NO3^--N会产生 相似文献
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