钾肥对香稻香气及稻米品质的影响

Effects of Potassium Fertilizer on Aroma and Quality of Aromatic Rice

为了探明钾肥对香稻香气及稻米品质的影响,为香稻生产施用适宜钾肥提供理论依据.设置了4个钾肥水平,依次为施K2O 0 kg/hm^2 （K0）、37.5 kg/hm^2（K1）、112.5 kg/hm^2 （K2）和187.5 kg/hm^2（K3）,以常规香稻品种“桂香占”和“农香18”为材料进行大田对比试验,对不同钾肥水平下香稻游离脯氨酸含量、脯氨酸脱氢酶活性、糙米香气2-AP含量、钾素积累总量和稻米品质等方面进行系统的比较研究.结果表明,与不施钾处理K0比较,施钾处理显著提高了2个香稻品种的糙米香气2-AP含量,增幅达10.70 ％～67.65％,这主要得益于施钾处理普通提高了香稻的游离脯氨酸含量和脯氨酸脱氢酶活性,其中,桂香占以K2处理的香气最高,较其它处理增高5.31％ ～67.65％.农香18以K3的香气最高,较其它处理增高25.72 ％～40.04％.经二次曲线模拟,在施钾量为K2O 123.46和187.50 kg/hm^2时,桂香占和农香18在本试验条件下分别获得最高香气含量.此外,钾肥还降低了垩白粒率和垩白度,提高了蛋白质含量和直链淀粉含量,而对稻米的加工品质影响较小.施钾量与稻米品质的相关性分析也表现出与此类似的结果.因此,钾肥能够提高香稻品种的糙米香气含量,并对香稻的稻米品质具有一定的改善作用.兼顾两香稻品种香气对钾肥施用量的反应,在本试验条件下,较适宜的钾肥施用量为112.5 ～ 187.5 kg/hm^2.

In this paper,the effects of potassium fertilizer on the aroma and quality of aromatic rice were investigated to provide theoretical basis for suitable potassium fertilizer application rate in aromatic rice production.A field contrast experiment was conducted with two conventional aromatic rice cultivars ‘ Guixiangzhan’ and ‘ Nongxiang 18’,using four potassium levels followed by K2O 0 kg/hm^2 （K0）,37.5 kg/hm^2 （K1）,112.5 kg/hm^2 （K2） and 187.5 kg/hm^2 （K3）,the effects of different potassium levels on the free proline content,proline dehydrogenase activity,2-Acetyl-1-pyrroline（2-AP） contents,total K accumulation and quality of aromatic rice were evaluated.The results showed that compared with K0,potassium fertilizer could significantly increase 2-AP the contents of two aromatic rice cultivars,with an increase of 10.70 %-67.65 %,as potassium fertilizer could generally improve the free proline content and proline dehydrogenase activity of aromatic rice,the highest 2-AP content of Guixiangzhan was treated by K2,with an increase of 5.31%-67.65 %,compared with others.The highest 2-AP content of Nongxiang 18 was treated by K3,with an increase of 25.72 %-40.04 %,compared with others.Simulated by a quadratic curve,the 2-AP contents of Guixiangzhan and Nongxiang 18 reached their maxima under potassium fertilizer application rate of K2O 123.46 and 187.50 kg/hm^2.In addition,potassium fertilizer could decrease chalky rice rate and chalkiness degree.On the contrary,potassium fertilizer could improve protein content and amylase content,but potassium fertilizer had little effect on the processing quality of rice.Potassium fertilizer could promote 2-AP contents in aromatic brown rice and had a certain improvement to the quality of aromatic rice.Under the experimental conditions,taking into account of the aroma reactions of two aromatic rice cultivars for potassium fertilizer,the suitable fertilizers application rate was 112.5-187.5 kg/hm^2.