施氮量对马铃薯块茎淀粉积累及相关超微结构的调节效应

Effects of nitrogen application on starch accumulation and related ultrastructure in potato tuber

为明确施氮量对不同淀粉型马铃薯块茎淀粉积累及相关超微结构的调节效应,选用高淀粉品种‘克新22号’和低淀粉品种‘克新19号’,设置0(CK)、75、150、225和300 kg/hm^(2)共5个施氮量处理,测定不同施氮量处理的块茎淀粉含量、淀粉产量以及块茎淀粉粒、淀粉体的个数和粒径,并分析了马铃薯块茎淀粉含量与淀粉粒、淀粉体之间的关系。结果表明:施氮量在0~300 kg/hm^(2)时,‘克新22号’和‘克新19号’品种块茎的淀粉含量随施氮量的增加呈不断降低的趋势。其中施氮量为0(CK)kg/hm^(2)时,2个品种的块茎淀粉含量均达最高。2个品种块茎的淀粉产量随施氮量的增加则呈先增加后降低的趋势。其中施氮量为150 kg/hm^(2)时,高淀粉品种‘克新22号’块茎的淀粉产量达到最高,为11.27 t/hm^(2);而低淀粉品种‘克新19号’施氮量为225 kg/hm^(2)时,块茎淀粉产量达到最高,为8.99 t/hm^(2)。2个品种块茎淀粉粒和淀粉体的数量均随施氮量增加呈不断减少的趋势,淀粉粒和淀粉体的平均粒径随施氮量增加均呈不断变小的趋势,2个品种块茎微观淀粉粒的含量随施氮量增加呈不断降低的趋势,与块茎的淀粉含量随施氮量的增加呈不断降低的趋势一致。2个品种块茎中粒径(d)<30μm的淀粉粒和淀粉体所占比例均随施氮量的增加呈不断增加的趋势,d≥30~50和≥50μm的淀粉粒和淀粉体所占比例均随施氮量的增加呈不断降低的趋势。其中施氮量为0(CK)kg/hm^(2)时,2个品种块茎中淀粉粒和淀粉体的数量最多、粒径最大,d<30μm的淀粉粒和淀粉体所占比例最低,d≥30~50和≥50μm的淀粉粒和淀粉体所占比例最高。综上所述,不同淀粉型马铃薯块茎淀粉积累及相关超微结构受施氮量的影响较大;应根据不同淀粉型马铃薯块茎的淀粉含量、淀粉产量及淀粉粒和淀粉体等超微结构的变化确定品种适宜的施氮量。

In order to determine the regulatory effects of nitrogen application on starch accumulation and related ultrastructure in potato tuber of different starch type varieties,the high-starch variety‘Kexin 22’and low-starch variety‘Kexin 19’were selected and treated with nitrogen application rates of 0(CK),75,150,225 and 300 kg/hm^(2),respectively.The starch content,starch yield and the number and particle size of starch granules and amyloid bodies in tubers under different nitrogen application were measured.The relationship between starch content and starch granules and amyloid bodies in potato tubers was analyzed.The results showed that:The starch content of tubers of‘Kexin 22’and‘Kexin 19’varieties decreased with the increase of nitrogen application rate when nitrogen application rate was 0 to 300 kg/hm^(2).The starch content of tuber of the both varieties reached the highest values when nitrogen application rate was 0(CK)kg/hm^(2).The starch yield of tuber of the two varieties increased first and then decreased with the increase of nitrogen application.When the nitrogen application rate was 150 kg/hm^(2),the starch yield of high-starch variety‘Kexin 22’reached the highest,which was 11.27 t/hm^(2).The starch yield of low-starch variety‘Kexin 19’reached 8.99 t/hm^(2) when the nitrogen rate was 225 kg/hm^(2).The number of starch granules and amyloid bodies in the tubers of the two varieties showed a decreasing trend with the increase of N application rate,and the average particle size of starch granules and amyloid bodies showed a decreasing trend with the increase of N application rate,resulting in a decreasing trend of microscopic starch granule content in the tubers of the two varieties with the increase of N application rate.It was consistent with the decreasing trend of starch content in the tubers with the increase of N application rate.The proportion of starch granules and amyloid bodies with diameter(d)<30μm increased with the increase of N application rate,and the proportion of starch granules and amyloid bodies(d≥30-50μm and≥50μm)decreased with the increase of N application rate.When the nitrogen rate was 0(CK)kg/hm^(2),the number and size of starch granules and amyloids of the two varieties were the largest,the proportion of starch granules and amyloids(d<30μm)was the lowest,and the proportion of starch granules and amyloids(d≥30-50 and≥50μm)was the highest.In conclusion,the starch accumulation and related ultrastructure of potato tubers of different starch potato varieties were greatly affected by nitrogen application.Therefore,the suitable nitrogen application should be determined according to the starch content,starch yield and ultrastructure changes of starch granules and starch bodies in the tubers of different starch type potato varieties.