新疆药用植物黑桑的抗氧化性

为寻找一种天然的抗氧化材料,以新疆药用植物黑桑的根、枝、叶和果实的乙醇提取物为材料,进行总多酚、总黄酮、抗氧化能力以及螯合 Fe2+测定。结果显示：果实(桑椹)提取物(EEMF)的总多酚含量(0.9438 mg· mL -1)以及总黄酮含量(0.1747 mg·mL -1)与叶提取物( EEML)、枝提取物( EEMB)和根提取物( EEMR)相比并不高,但 EEMF的抗氧化能力最强,其清除羟基自由基、DPPH 自由基能力分别达到96.46%,96.83%,抑制脂质体氧化能力达到71.14%;此外,EEMF螯合 Fe2+能力也强于其他3种。表明黑桑4个部位都具有良好的抗氧化能力,且果实最佳。     

供铁水平对不同苹果基因型生长及根系特性的影响

以小金海棠 (MalusxiaojinensisChengetJiang)和山定子 (MalusbaccataL .Borkh)为试材 ,研究供铁水平对其生长及根系特性的影响 ,结果表明 ,在幼苗生长量、新叶叶绿素含量、营养液pH日变化、根系活力、根系ATP酶活性诸方面 ,存在基因型差异。同一供铁水平 ,小金海棠有明显的铁胁迫反应 ,而山定子铁胁迫反应较弱。低铁胁迫处理 ,小金海棠叶片叶绿素含量、根系活力、根系ATP酶活性皆明显高于山定子。根系活力及根系ATP酶活性可用作铁高效基因型植物的筛选指标     

内蒙古锡林浩特地区土壤-牧草-家畜系统中Cu、Fe、Zn、Mn、Mg、Se六种元素含量的分析

对内蒙古锡林浩特地区土壤，牧草，家畜（羊）被毛中6种元素含量进行了测定。结果表明：土壤硒含量于缺乏的临界水平；尖草，羊草及针草中锌含量低于羊正常生长对锌的需求数量，兔毛草及羊草中的硒的含量很低，不能满足其正常生长需要，被毛中硒含量低于临界值，提示羊群缺硒。     

不同施肥处理土壤胡敏酸及其级分 与 Fe2+的络合特征 Ⅰ.胡敏酸原样与 Fe2+的络合特征

采用 17年不同施肥处理 (无肥、化肥、秸秆、厩肥 )土耕层土样 ,在对土壤胡敏酸性质研究的基础上 ,着重研究不同施肥处理土壤胡敏酸与Fe2+的络合特征 ,揭示络合作用与胡敏酸性质以及环境条件的关系。结果表明 ,不同施肥处理土壤胡敏酸与Fe2+的络合能力不同。和无肥处理相比 ,化肥处理胡敏酸的络合能力加强 ,logk值 (络合稳定常数 )增大 ,有机肥处理则使胡敏酸的络合能力下降 ,logk值减小。logk值大小与胡敏酸的羧基、酚羟基以及总酸度有关。pH值、温度、离子强度是影响络合稳定常数大小的环境因素 ,pH值由 4到 7,各处理胡敏酸的logk值增大 ,络合配位数也有增加趋势。温度升高 ,离子强度增大 ,logk值降低。胡敏酸与Fe2+络合反应是一个自发的放热反应 ,络合后整个体系的有序性增强 ,熵值减小。     

影响菜豆体内铁再利用效率的因素及其机理

本文在人工气候室中，用营养液培养方法，并结合同位素示踪技术研究了铁的供应状况，两种形态氮素（ＮＯ＾－３－Ｎ和ＮＨ＾＋４－Ｎ）及叶处遮光对菜豆体内铁再利用效率的影响，并对其有关机理进行了深入的研究。结果表明，铁的缺乏有利于累积在根和初生叶中的铁身新生组织中转移，铁的再利用效率明显提高。无论有缺铁还供铁条件下，ＮＨ＾＋４－Ｎ的供应使得菜豆新叶中活性铁含量、新叶叶绿素含量及体内铁的再利用效率都明显高于Ｎ     

腐殖质对白浆土中Fe、Mn、Al形态转化及磷生物有效性的影响

在三江平原布置长期试验，研究连年施用有机肥后土壤腐殖质变化及其对白浆±Fe、Mn、Al形态转化及磷生物有效性的影响。结果表明，施用牛粪后土壤腐殖质含量升高，且以松结态腐殖质的增长为主；土壤的DTPA提取态和有机络合态Fe、Mn、Al含量上升，使土壤有效态磷含量上升。因此，生物措施是治理白浆土，促进土壤磷素养分有效性上升，增大土壤缓冲容量和抗逆性的有效措施。     

硅锰结合施用对红壤水稻铁毒害的矫正

Based on the fact that Fe toxicity which is usually characterized by leaf oranging and low yield can be obviously subdued by application of Si or Mn due to counteraction.between Fe and Si or Mn.A pot experiment was conducted with four treatments of CK,Si,Mn and Si Mn to further study the effect of combined application of Si and Mn on rice growth on red earths.Water-soluble SI,Fe and Mn were measured.and electron probe was used to study Si,Mn,Fe and Ca in root cross sections.Combined application of Si and Mn could increas water-soluble Si and Mn but reduce water-soluble Fe,thus being favorable for correctiong Fe toxicity.Electron probe study showed obvous differences of Si,Fe,Mn,and Ca in rice roots between CK and the other three treatments.The combined applicatioin of Si and Mn could reduce leaf oranging and improve rice growth.The Si Mn treatment had a higher plant height,lower number of oranging leaves and a 25.0% higher rice yield than CK and showed a better effect on rice growth than the treatment of sole Si or Mn.     

Influence of green manuring with Sesbania rostrata and Aeschynomene afraspera or urea on dynamics and uptake of nutrients by wetland rice

Nutrient concentrations in the soil and crop uptake from incorporated green manure and urea in flooded rice was studied in field experiments. Release of plant-available nitrogen (NH₄ ⁺-N) from green manure was slightly delayed compared with that from prilled urea (PU) because Sesbania rostrata L. and Aeschynomene afraspera L. released the N gradually after their decomposition, whereas N became available immediately after PU application. Exchangeable NH₄ ⁺-N concentration in soil peaked at 163 mg kg^–1 in the transplanted rice (TPR) and 198 mg kg^—1 in broadcast-seeded rice (BSR) at 0 and 1 week after PU application. Broadcast-seeded rice depleted NH₄ ⁺-N faster than did TPR because of the crop‘s vigorous growth in the former during the early stage. Soil solution NH₄ ⁺-N followed a similar trend to that of soil NH₄ ⁺-N. Incorporation of S. rostrata and A. afraspera increased the concentration of P, K⁺, Fe²⁺ and Mn²⁺ in soil solution more than did the application of PU. However, zinc concentration decreased in all treatments. Both PU and green manure increased the N status of the rice plants and enhanced the uptake of P, K, Fe, Mn and Zn by the rice crop. This suggests that application of green manures improves the uptake of these nutrients by the crop. The highest apparent N recovery was obtained with PU followed by green manure. Received: 11 November 1996     

不同施肥处理对连作大豆白浆土中Cu、Zn、Fe、Mn含量的影响

不同施肥处理对连作大豆白浆土中 Cu、Zn、Fe、Mn含量的影响不同。长期施用有机肥和秸秆还田不仅提高土壤中 Mn、Zn和 Fe的含量 ,而且也使 Cu、Zn、Fe有效性增高 ;长期不施肥土壤全 Cu、Zn、Mn、Fe及有效态 Zn、Mn含量呈下降趋势 ,而单施化肥土壤中全 Cu和 Zn含量略有升高。