SWEET(sugars will eventually be exported transporter)基因家族是一类新型的糖转运蛋白,可顺浓度梯度对糖分进行双向跨膜运输。SWEET在植物光合同化物韧皮部装载、蜜腺花蜜分泌、种子灌浆、花粉发育、病原菌互作、逆境调控等过程中起着关键作用,近年来受到广泛关注。尽管SWEET广泛存在于植物中,但目前对其功能研究主要集中在水稻和拟南芥上。介绍了SWEET基因家族的发现、蛋白结构特征、生理功能及逆境调控的最新研究进展,有助于将来对SWEET基因家族进行更深入和全面的研究。
【目的】青花菜是硫代葡萄糖苷含量非常高的十字花科蔬菜,大量医学和营养学研究表明,青花菜具有防癌抗癌的显著功效,其防癌抗癌特性主要与硫代葡萄糖苷的多种降解产物有关,尤其是4-甲基硫氧丁基硫苷(RAA)和3-甲基吲哚基硫苷(GBC)的降解产物。本研究拟建立青花菜抗癌硫代葡萄糖苷的近红外光谱快速测定方法。【方法】采用高效液相色谱法(HPLC)测定青花菜中硫代葡萄糖苷RAA和GBC的含量,将近红外光谱仪扫描样品所获得的光谱文件与化学分析结果在偏最小二乘回归法(partial least squares,PLS)分析的基础上,采用不同的散射处理方式(SNV、Detrend、SNV+Detrend)和导数处理方式(FD、SD)对光谱数据进行预处理,从而得到定标方程,再进一步对模型进行验证。【结果】4-甲基硫氧丁基硫苷(RAA)和3-甲基吲哚基硫苷(GBC)是青花菜中存在的主要硫苷,占总含量的60%以上。90份青花菜的硫苷组分含量结果表明RAA平均含量最高,含量变化范围最大,平均含量为6.20μmol·g-1,变化范围为0.66—14.54μmol·g-1;GBC平均含量为4.43μmol·g-1,变化范围为0.25—10.79μmol·g-1。经过筛选,采用SNV+SD处理后RAA预测模型的校正集和预测集相关系数分别为0.867和0.912;采用SNV+SD处理后的GBC预测模型的校正集和预测集相关系数分别为0.918和0.960。【结论】建立了RAA和GBC的近红外光谱快速检测模型,为青花菜营养品质的快速检测、优异抗癌青花菜种质资源的快速筛选与利用奠定了基础。
Pot experiments were carried out to investigate the effects of a complex amendment on the soil organic matter content, pH, microbial quantity, Cd uptake and nutritional quality of the fruit of cucumber （Cucumis sativus L.） planted in two levels （CdCl2·2.5H2O mg/kg and 4 mg/kg） of Cd-contaminated soil in which different concentrations of complex amendments （0, 600, 900, 1 200 mg/kg） were added. The results showed that when applying 1 200 mg/kg amendment, the organic mat-ter content, bacterial number and total microorganism amounts in 2 and 4 mg/kg Cd-contaminated soil increased by 23.17% and 32.89%, 87.61% and 96.02%, 59.95% and 55.81%, respectively. When 900 mg/kg amendment was applied, the fungi number in 2 and 4 mg/kg Cd-contaminated soil reached the maximum, in-creasing by 137.50% and 106.72% respectively. However, applying the amendment had no significant effect on the pH of soil. The security and nutritional quality of cu-cumber fruits were obviously improved comparing with control. The Cd content in cucumber fruits decreased by 31.40% and 24.35%, respectively, in 2 and 4 mg/kg Cd-contaminated soil. Furthermore, Vc, soluble sugar and soluble fixation content in cucumber fruits of 2 and 4 mg/kg Cd-contaminated soil went up by 25.00% and 91.42%, 37.03% and 27.06%, 14.29% and 58.80%, respectively. lt was indicated that the complex amendment can obviously improve the quality of cucumber fruit and thus can be used in the in situ_repair of Cd-contaminated soil.
