稻田温室气体减排措施对稻米氨基酸含量的影响

为探索稻田中温室气体减排措施对稻米氨基酸含量的影响,用10个不同方法对双季稻田进行处理,并使用高效液相色谱分别测定了各处理稻田中所产稻米中的16种氨基酸的含量,其中色谱柱为Agilent Zorbax AAA分析柱,柱前衍生使用邻苯二甲醛(OPA)和9-芴甲基氯甲酸酯(FMOC-CL)为衍生试剂。结果发现:1)10个处理中的稻米16种氨基酸种类齐全,施氮肥+添加生物质炭48 t/hm2+间歇灌溉(NPK+HBC+IF)处理中所得氨基酸总量为6520.7 mg/100g,效果最佳;对照组处理(不施加氮肥+无稻草还田+间歇灌溉)所得氨基酸含量4338.0 mg/100g为最低。以对照组处理所得必需氨基酸百分含量36.8%为最高值;无稻草还田+长期淹水(NPK+CF)处理方法所得必需氨基酸百分含量33.1%为最低值。10个处理中16种氨基酸中含量较高的氨基酸均为天冬氨酸、谷氨酸和精氨酸,含量最低的均为甲硫氨酸;2)施氮肥量相同时,长期淹水与间歇灌溉相比,氨基酸总量增加185.1 mg/100g,非必需氨基酸百分含量增加3%,谷氨酸、组氨酸和丝氨酸含量明显升高,但亮氨酸含量显著降低;3)施用氮肥能提高稻米中的氨基酸含量,且随着氮肥使用量的增加,氨基酸含量也随之增加,组氨酸含量增加显著;4)供氮量相同时,添加猪粪使氨基酸总含量升高了286.0 mg/100g,此结果表明,在供氮量相同的情况下,施用猪粪更有利于稻米氨基酸含量的提高;5)灌溉模式相同时,稻草还田配施氮肥对必需氨基酸和氨基酸总量均有提高,天冬氨酸、谷氨酸和组氨酸的含量增加较多,甲硫氨酸含量略有下降;随着稻草还田量的增加,对非必需氨基酸影响较为明显;当稻草半量还田(还田量为3 t/hm2)时,稻米中氨基酸总量增加最多;稻草全量还田+长期淹水(NPK+HRS+CF)与稻草半量还田+间歇灌溉(NPK+LRS+IF)处理中的氨基酸含量基本接近,但必需氨基酸含量前者略高于后者,说明稻草还田与水肥管理对氨基酸含量影响可能存在交互作用;6)添加生物质炭配施氮肥提高了稻米必需氨基酸与非必需氨基酸含量,且随着生物质炭添加量的增加而增加;与稻草还田、添加猪粪处理相比,生物质炭的添加对氨基酸总含量提升的效果最为显著,对稻田实际生产具有指导意义且具有一定的环境效益。

The effect of rice field greenhouse gas emission reduction practice on the contents of amino acids in rice grains

To investigate the effect of greenhouse gas emission mitigation practices on a double-rice paddy field on the contents of amino acids in rice grains, sixteen amino acid derivatives under ten different treatments were analyzed. High-performance liquid-chromatography with an Agilent Zorbax AAA column was used, and an online pre-column derivatization method was adopted by using o-phthaldialdehyde (OPA) and 9-Fluorenylmethyl chloroformate (FMOC-CL) as the derivatization regent. Results showed that the rice grains of the ten treatments all included sixteen amino acids and species. When a combination of nitrogen fertilizer with addition of biochar at 48 t/hm² and intermittent irrigation (NPK+HBC+IF) was used as a treatment, the total amino acid contents were 6520.7 mg/100g, which was the highest in all treatments. Application of intermittent irrigation with no fertilizer was used as a control and this achieved the lowest total amino acid contents at 4338.0 mg/100g. The fraction of essential amino acids was highest at 36.8% in the control treatment. The nitrogen fertilizer with continuous irrigation (NPK+CF) treatment method achieved the lowest fraction of essential amino acids, at 33.1%. The contents of Aspartic Acid, Glutamic acid and Arginine in sixteen amino acids of rice grains were higher, while Methionine was lower in ten treatments. Second, with a treatment of nitrogen fertilizer with continuous irrigation, the total amino acid contents increased by 185.1 mg/100g and the fraction of non-essential amino acids increased by 3% in rice grains compared with a nitrogen fertilizer (the same amount) and intermittent irrigation treatment. The contents of Glutamic acid, Histidine and Serine were increased, while the content of Leucine was significantly decreased with the latter treatment. Third, the application of nitrogen fertilizer had a remarkable effect on the content of Histidine, and enhanced the amino acid contents in rice grains, which was increased with the increasing of nitrogen fertilizer application rates. Fourth, with the same amount of nitrogen fertilizer, the addition of pig manure resulted in an increase of 286.0 mg/100g in total amino acid contents, which indicated that addition of pig manure was better for the improvement of total amino acids contents in the condition of constant nitrogen fertilizer. Fifth, the rice straw incorporation treatment also increased the content of total amino acids and essential amino acids. The contents of Aspartic Acid, Glutamic acid and Histidine were increased, while the content of Methionine was decreased. The increase of returning crop straw obviously affected non-essential amino acid contents and the total amino acid contents were higher at half crop straw return (3 t/hm²). The total amino acid contents of total crop straw return with continuous irrigation (NPK+HRS+CF) was similar to that of the half crop straw return with intermittent irrigation treatment (NPK+LRS+IF), but the essential amino acid content was higher for the former. This phenomenon indicated that rice straw incorporation along with the management of water and nitrogen fertilizer might have an interaction effect on the content of amino acids. Finally, addition of biochar combined with nitrogen fertilizer greatly improved the essential and non-essential amino acid contents in rice grains, and its performance was positively correlated with its application rates. Based on these collective data, the addition of biochar in paddy fields performed better than other treatments for improving the total amino acid contents in rice grains, and this practice was beneficial for realistic production in rice fields and environment protection.