Antonious George F, Bomford Michael, Vincelli Paul
Department of Plant and Soil Science, Land Grant Program, Atwood Research Center, Kentucky State University, Frankfort, Kentucky 40601-2355, USA.
J Environ Sci Health B. 2009 Mar;44(3):311-6. doi: 10.1080/03601230902728476.
Glucosinolates (GSLs), a group of compounds found in Brassica plants, are toxic to some soil-borne plant pathogens because of the toxicity of their hydrolysis products, isothiocyanates. Other phytochemicals found in Brassica plants, such as phenols and ascorbic acid, may compliment the activity of GSLs. A survey of Brassica accessions from the national germplasm repository was conducted to identify potential cover crops that could be soil-incorporated for use as biofumigants. Ten Brassica accessions that demonstrated relative cold tolerance, rapid maturity, and superior biomass production were selected. The selected accessions were grown under three climatic conditions (fall greenhouse, winter high tunnel, and spring field) to investigate whether growing conditions affect their GSL, phenol, and ascorbic acid content. The selected accessions included seven accessions of Brassica juncea (Indian mustard), one of Brassica napus (oil seed rape), one of Brassica campestris (field mustard), and one of Eruca sativa (arugula). Separation of GSLs from the selected Brassica accessions was achieved using ion-exchange sephadex in disposable pipette tips. Quantification of total GSLs was based on inactivation of the endogenous thioglucosidase and liberation of the glucose moiety from the GSL molecule by addition of standardized thioglucosidase (myrosinase) and colorimetry. GSL concentration of greenhouse, high tunnel, and field-grown shoots (leaves and stems) averaged 24, 40 and 76 micromoles g(-1) fresh weight, respectively. Accessions of B. juncea generally had the highest GSL content. A comparison of accessions revealed that Ames 8887 of B. juncea contained the greatest GSL concentration, but had the lowest biomass yield and ascorbic acid concentration, in part because phytochemical concentration tended to be negatively correlated with biomass yield. More promising was B. juncea accession 'Pacific Gold' which coupled high biomass yield with above-average GSL production, but had low phenol and ascorbic acid concentration. We concluded that environmental stress on growing plants can increase the concentration of GSLs, ascorbic acid, and total phenols in Brassica shoots, but does not increase yields of these phytochemicals per unit area.
硫代葡萄糖苷（GSLs）是一类存在于十字花科植物中的化合物，由于其水解产物异硫氰酸盐具有毒性，因而对一些土壤传播的植物病原体有毒害作用。十字花科植物中发现的其他植物化学物质，如酚类和抗坏血酸，可能会增强硫代葡萄糖苷的活性。对国家种质资源库中的十字花科种质进行了一项调查，以确定可用于土壤掺入作为生物熏蒸剂的潜在覆盖作物。选择了10个表现出相对耐寒性、早熟和高产生物量的十字花科种质。将选定的种质在三种气候条件下（秋季温室、冬季高拱棚和春季田间）种植，以研究生长条件是否会影响它们的硫代葡萄糖苷、酚类和抗坏血酸含量。选定的种质包括7个芥菜型油菜（印度芥菜）种质、1个甘蓝型油菜（油菜籽）种质、1个白菜型油菜（田芥菜）种质和1个芝麻菜种质。使用一次性移液器吸头中的离子交换葡聚糖凝胶从选定的十字花科种质中分离出硫代葡萄糖苷。总硫代葡萄糖苷的定量基于内源性硫代葡萄糖苷酶的失活以及通过添加标准化硫代葡萄糖苷酶（黑芥子酶）和比色法从硫代葡萄糖苷分子中释放出葡萄糖部分。温室、高拱棚和田间种植的嫩枝（叶和茎）的硫代葡萄糖苷浓度平均分别为24、40和76微摩尔/克鲜重。芥菜型油菜种质通常硫代葡萄糖苷含量最高。种质比较显示，芥菜型油菜的Ames 8887硫代葡萄糖苷浓度最高，但生物量产量和抗坏血酸浓度最低，部分原因是植物化学物质浓度往往与生物量产量呈负相关。更有前景的是芥菜型油菜种质“太平洋黄金”，它具有高生物量产量和高于平均水平的硫代葡萄糖苷产量，但酚类和抗坏血酸浓度较低。我们得出结论，生长中的植物受到的环境胁迫会增加十字花科嫩枝中硫代葡萄糖苷（GSLs）、抗坏血酸和总酚的浓度，但不会增加这些植物化学物质的单位面积产量。
