大蒜不同品种硝酸盐积累规律研究

Patterns of Nitrate Accumulation in Different Garlic Varieties

以26个大蒜品种为试验材料，分析了不同品种不同生长期和不同产品器官硝酸盐积累特点，结果表明：大蒜不同生长时期和不同产品器官中硝酸盐积累量不同，叶片和叶鞘中硝酸盐含量在生长旺盛的春季（4月5日）和早春（3月14日）明显高于冬季（1月7日）；不同器官以蒜苗中最高，蒜薹中次之，蒜头中最低；蒜苗中硝酸盐含量多为叶鞘高于叶片。大蒜不同品种间叶鞘、叶片、蒜薹和蒜头中硝酸盐含量均有极显著差异，按照沈明珠等的4级分类标准，3个品种叶鞘中，9个品种叶片中，4个品种蒜薹中，22个品种蒜头中的硝酸盐含量均低于432mg／kg，属轻度积累；大蒜中硝酸盐含量最高仅达到三级（785～1440mg／kg），属高度积累。依据国家标准（GB18406．1—2001），大蒜不同品种的各产品器官中硝酸盐含量均未超出限量指标。

The study investigated nitrate accumulations of different garlic varieties at different growth stages and in different parts,revealing that in the garlic varieties,nitrate accumulations differed among different growth stages and different productive parts, clearly higher in the leaf blades and sheathes in early spring （March 14） and spring （April 5） when garlic was vigorously growing than in autumn （January 7）. Of all the parts of the garlic varieties,the sprouts had the highest nitrate accumulation,the bolts took the second place in nitrate accumulation and the bulbs had the lowest nitrate accumulation;in garlic sprouts the nitrate contents in the leaf sheathes was higher than that in the leaf blades. Different garlic varieties had greatly different nitrate contents in their leaf sheathes, leaf blades, sprouts and bulbs and according to the fourgrade classification system developed by Shen Mingzhu et al,the nitrate contents was below 432 mg/kg in the leaf sheathes of three varieties ,the leaf blades of nine varieties, the sprouts of four varieties and the bulbs of 22 varieties,indicating light accumulation and in the garlic variety the maximum nitrate accumulation reached Grade 3 （785～1 440 mg/kg）,indicating high nitrate accumulation. According to the national classification standard （GB18406.1-2001） the nitrate contents in different productive parts of the varieties did not surpass the nitrate content ceiling.