稀土对UV-B胁迫下大豆蛋白质含量和氨基酸组成的影响及营养评价

摘要

为探究稀土对UV-B辐射增强条件下大豆产量和品质的影响,以大豆东农42为材料,盆栽条件下紫外灯照射处理,自然光照不喷稀土对照组为CK1,紫外光照不喷稀土对照组为CK2.大豆初花期喷施30、60和90 mg· L-1LaCl3和90、120、150 mg·L-1CeCl3溶液,研究UV-B辐射增强条件下稀土镧和铈对大豆籽粒氨基酸组分、蛋白质含量、产量和营养价值的影响规律.利用氨基酸自动分析仪和凯氏定氮法分别测定大豆籽粒氨基酸组成及蛋白质含量,采用FAO/WHO氨基酸评分模式计算大豆籽粒蛋白质的氨基酸评分(AAS)、化学评分(CS)、氨基酸比值系数分(SRC)和必需氨基酸指数(EAAI),评价稀土镧、铈对大豆籽粒蛋白质营养价值的影响.结果表明,喷施稀土对大豆籽粒必需氨基酸、蛋白质和产量均有一定促进作用,缓解UV-B辐射胁迫.在UV-B辐射条件下,60 mg· L-1 LaCl3处理大豆产量最高,较CK2显著增加69.03％;30 mg· L-1 LaCl3处理的大豆蛋白质含量、必需氨基酸和氨基酸总量最高,较CK2分别增加14.25％ (P＜0.05)、20.62％和25.96％.蛋氨酸和胱氨酸是高蛋白型大豆东农42的第一限制性氨基酸.120 mg· L-1 CeCl2的AAS、CS、SRC最高值分别为60.44,46.72和68.93;150 mg· L-1CeCl3的EAAI最高且比CK1高1.90,说明稀土铈可提高大豆籽粒蛋白质营养价值.%To explore the effect of rare earth on soybean yield and quality under ultraviolet-B radiation enhanced condition.The soybean Dongnong 42 as used for experiment material which planted in the pot with ultraviolet lamp irradiation treatment.The control group of natural light not spraying rare earth was CK1,and the control group of ultraviolet light not spraying rare earth was CK2.The test by spraying concentration of 30,60 and 90 mg· L-1 of LaCl3 solution and 90,120 and 150 mg· L-1 of CeCl3 solution at soybean initial flowering stage of soybean,in order to study the effect of rare earth on amino acid component,protein content,soybean yield and nutritional value of soybean seed.Using the amino acid automatic analyzer and the kjeldahl method to study the rare earth effect on the amino acid composition and protein.The protein nutritive value of soybean seed was evaluated and compared by computing amino acid score (AAS),chemical score (CS),score of ratio coefficient of amino acid (SRC) and essential amino acid index (EAAI) according to FAO/WHO scoring pattern.The results showed that suitable concentration of rare earth could increase the essential amino acid and protein and yield of mature soybean seed.And it had a mitigative effect to UV-B radiation.Spraying rare earth solution could increase the content of yield,and the maximum increase was 69.03 ％ (P＜0.05) comparing with CK2.The protein total essential amino acids and total amino acids reached the highest in spraying 30 mg· L-1 LaCl3,which were 14.25 ％(P＞0.05),20.62％ and 25.96％.The first limiting amino acids were methionine and cystine.The AAS,CS and SRC under the treatment of 120 mg· L-1 CeCl3 were 60.44,46.72 and 68.93,respectively,the above values were higher than these of other treatment groups.EAAI increased by 1.90 higher than CK1 under 150 mg· L-1 LaCl3 treatment.The above results showed that the cerium could increase the nutritive value of soybean seed protein.