海水磷酸盐分析方法的优化和试剂稳定性研究

对《海洋调查规范》中测定海水磷酸盐的常规方法进行了优化 ,达到了简化过程 ,缩短分析时间以适应水下现场自动分析的目标。此外 ,实验还对磷酸盐测定所使用的试剂及标准贮备液的稳定性进行了一系列的研究 ,改进试剂保存方法 ,延长试剂使用寿命 ,以满足长期现场测定的要求     

Assessment of the effect of time and temperature on the availability of residual phosphate in a glasshouse study of four soils using the Olsen method

Abstract. The Olsen method is an indicator of plant-available phosphorus (P). The effect of time and temperature on residual phosphate in soils was measured using the Olsen method in a pot experiment. Four soils were investigated: two from Pakistan and one each from England (calcareous) and Colombia (acidic). Two levels of residual phosphate were developed in each soil after addition of phosphate by incubation at either 10 °C or 45 °C. The amount of phosphate added was based on the P maximum of each soil, calculated using the Langmuir equation. Ryegrass was used as the test crop. The pooled data for the four soils incubated at 10 °C showed good correlation between Olsen P and dry matter yield or P uptake ( r ²= 0.85 and 0.77, respectively), whereas at 45 °C, each soil had its own relationship and pooled data did not show correlation of Olsen P with dry matter yield or P uptake. When the data at both temperatures were pooled, Olsen P was a good indicator of yield and uptake for the English soil. For the Pakistani soils, Olsen P after 45 °C treatment was an underestimate relative to the 10 °C data and for the Colombian soil it was an overestimate. The reasons for these differences need to be explored further before high temperature incubation can be used to simulate long-term changes in the field.     

磷化氢的生物合成

磷化氢（PH3）是有毒、致癌、无色、有恶臭味的气体，既可由工业化学合成，也可由生物合成。产PH3的微生物一般为兼性厌氧和专性厌氧微生物。借助于气相色谱检测，已发现PH3在自然界中广泛存在。热力学分析，磷酸盐还原成磷化氢是一种吸能反应。目前，磷化氢生物合成的具体机制还不清楚。     

施肥对金沙江干热河谷退化草地土壤微生物的影响

在金沙江干热河谷区的退化草地上进行了2年的氮磷施肥试验,试验结束后分析了土壤特性及土壤微生物数量和生物量的变化。结果表明,在施氮量为5 ,15g/ (m2 ·a)时,土壤微生物的数量和生物量均没有明显变化,而当施氮量增加到2 5g/ (m2 ·a)时,土壤微生物的数量和生物量比对照明显增加。施磷没有引起土壤微生物数量和生物量的明显增加。施氮和施磷均没有引起土壤细菌、真菌和放线菌组成的变化。这表明氮虽然影响土壤微生物的数量,但对土壤微生物的组成没有影响。施氮导致土壤硝态氮增加,但对氨态氮影响不大,硝态氮可能是影响土壤微生物数量的重要因素。施氮和施磷后植物群落地上生物量均出现增加的趋势,但土壤有机质没有明显增加。施氮和施磷也没有引起土壤pH和含水率的明显改变。我们的试验结果表明,在干热河谷退化草地生态系统,仅靠短期施用无机肥料恢复土壤微生物群落是困难的     

解磷菌剂对作物生长和土壤磷素的影响

利用课题组自行分离筛选的B2和B67解磷菌株研制的菌剂，在盆栽和大田试验过程中，菌剂在增加作物产量的同时，有提高土壤速效磷含量、培肥土壤的作用，而且是菌剂和化肥配合施用效果显著。施用了解磷菌剂或菌剂和化肥配合施用后，盆栽玉米的株高、鲜重和干重，较CK增加15．2％～89．2％，玉米单株吸养量较CK增加20％～146％；青菜的鲜重、干重和生物量较CK增加15．8％～41．6％，和CK比较差异显著；小麦的株高、有效小穗数、穗粒数、粒重以及生物量也较CK差异显著，大田试验的几种作物也有不同程度的增产。另外B2和B67接种到山西省典型土壤中，土壤速效磷含量较CK增加1．35～3．04倍，且发现其溶磷效果和土壤磷酸酶活性与有效活菌数相关，解磷菌剂在提高土壤速效磷含量的同时，也有提高土壤速效钾含量的作用。     

大鹏澳网箱养殖海域磷酸盐在沉积物-海水界面上换速率的研究

应用实验室培养法研究了大亚湾大鹏澳网箱养殖海域磷酸盐（PO4-P）在沉积物-海水界面上的交换通量;并根据改进的连续函数法计算了PO4-P在沉积物-海水界面上交换速率。结果表明：（1）PO4-P在沉积物-海水界面上的交换通量随时间的变化关系满足以e为底的指数衰减函数;（2）整个调查海域PO4-P在沉积物-海水界面上的交换速率为0.27~2.47 mmolm-2d-1。其中,网箱养殖区PO4-P的交换速率（0.82~2.47 mmolm-2d-1）明显高于对照区PO4-P的交换速率（0.27~0.62 mmolm-2d-1）,长时期的养殖活动使养殖区沉积环境中的磷得以积累,PO4-P在沉积物-水界面上的交换速率升高。     

Echinacoside promotes bone regeneration by increasing OPG/RANKL ratio in MC3T3-E1 cells

Echinacoside (ECH), isolated from Cistanche tubulosa (Schrenk) R. Wight stems, was subjected to in vitro experiments to investigate its bioactivities on proliferation, differentiation and mineralization of the osteoblastic cell line MC3T3-E1. MTT assay, the alkaline phosphatase (ALP) activity and calcium deposition were determined, and the secretion of collagen I (COL I), osteocalcin (OCN), osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) were also assayed by enzyme-linked immunosorbent assay (ELISA). The results showed that ECH caused a significant increase in cell proliferation, ALP activity, COL I contents, OCN levels and an enhancement of mineralization in osteoblasts at the concentration range from 0.01 to 10 nmol·L^− 1 (p < 0.05), suggesting that ECH has a stimulatory effect on osteoblastic bone formation or has potential activity against osteoporosis. In addition, the ratio of OPG/RANKL also could be enhanced by ECH. These findings provide the potent evidence that ECH can promote bone regeneration in cultured osteoblastic MC3T3-E1 cells, which might be done by elevating the OPG/RANKL ratio, and potential evidence for echinacoside to be a promising drug or a lead compound in the development of disease-modifying drug to prevent osteoporosis.