一氧化氮对NaCl胁迫下苜蓿种子萌发的影响

以甘农4号、阿尔冈金2个品种苜蓿为材料,用一氧化氮(NO)供体硝普钠、NO 清除剂c-PTIO、一氧化氮合酶抑制剂N-硝基-L-精氨酸甲脂、硝酸还原酶抑制剂钨酸钾及硝普钠类似物亚铁氰化钠(不产生NO)处理苜蓿种子,研究NO对盐胁迫下苜蓿种子萌发的生理效应。结果表明,盐胁迫显著抑制了2个苜蓿品种的发芽率、胚芽和胚根长及幼苗干重(P<0.05),降低种子萌发过程中α、β-淀粉酶、蛋白水解酶活性,抑制淀粉水解和可溶性糖积累(P<0.05);盐胁迫下添加外源NO则使2个品种苜蓿α、β-淀粉酶、蛋白水解酶活性、种子发芽率显著提高(P<0.05),淀粉含量降低,可溶性糖含量升高、胚芽和胚根长及幼苗干重显著增加(P<0.05);NO 供体SNP 的类似物亚铁氰化钠对盐胁迫下苜蓿种子萌发的各项指标无明显影响;施用NO 清除剂c-PTIO、硝酸还原酶抑制剂钨酸钾和一氧化氮合酶抑制剂N-硝基-L-精氨酸甲脂具有降低苜蓿种子萌发的效应(P<0.05)。因此,盐胁迫抑制苜蓿种子的萌发,而添加外源NO是缓解这种抑制作用的有效途径,内源NO也可能参与盐胁迫下苜蓿种子萌发的调节,且通过NOS和NR途径产生的NO在缓解盐胁迫抑制苜蓿种子萌发中可能起关键作用。     

Improving digestibility of soy flour by reducing disulfide bonds with thioredoxin

The Kunitz trypsin inhibitor (KTI) and the Bowman-Birk inhibitor (BBI) of trypsin and chymotrypsin contain disulfide bonds. Glycinin, the major storage protein in soybeans also contains disulfide bonds. Treatment of soy white flour with a NADP-thioredoxin system (NTS) effectively reduced disulfide bonds in soy flour and increased protein digestibility by trypsin and pancreatin as measured by the pH stat method. Treatment of soy flour with NTS increased the digestibility compared to soy white flour by 29.3 and 60.6% for trypsin and pancreatin, respectively. NTS-treated soy flour had similar digestibility by trypsin to autoclaved soy flour and casein, but digestibility by pancreatin was less than autoclaved soy flour and casein. The degree of reduction by NTS was highly correlated to the degree of hydrolysis (DH) by trypsin (R(2) = 0.93) and pancreatin (R(2) = 0.99). The DH of NTS-treated soy flour by trypsin is reflective of both inactivation of trypsin inhibitors and overall protein digestibility while pancreatin hydrolysis is reflective of only overall protein digestibility.     

Effect of Dehulling and Germination on Physicochemical and Pasting Properties of Black Beans (Phaseolus vulgaris L.)

Dehulled and/or germinated black bean flours were physicochemically characterized, including pasting properties, along with the trypsin inhibitor and antioxidant phenolics. To our best knowledge, this is the first study that, using nonparametric correlations and principal component analysis, identifies the parameters affecting the pasting properties of germinated black bean flour. The carbohydrate loss observed after black bean germination was indirectly correlated with the crude fiber content. Therefore, germination increased the protein and crude fiber contents compared with raw seeds (from 19.1 and 2.4% to 24.0 and 5.1%, respectively). Additionally, the highest protein digestibility was obtained in dehulled germinated black bean flour (78.4%), followed by whole germinated seed flour (74.1%). The dehulling process increased the total starch content 13.5 and 18.8% compared with raw and germinated whole bean flours, respectively. Dehulling decreased both trypsin inhibitor activity and antioxidant phenolics. Germination reduced by twofold the peak and final viscosities of black bean flours. Interestingly, both viscosities were negatively correlated with protein and positively correlated with fat and insoluble dietary fiber. Although resistant starch content was not affected by germination or dehulling, its interactions with fat and insoluble dietary fiber were responsible of the changes observed in pasting properties of germinated black bean flour.     

Studies on the nutritional composition and antinutritional factors of three different germplasm seed materials of an under-utilized tropical legume, Mucuna pruriens var. utilis

Two different germplasms of a white variety and one germplasm of a black variety of Mucuna pruriens var. utilis were evaluated for their physicochemical properties as well as their nutritional and antinutritional characteristics. All germplasms had higher grain weight, density, hydration, and swelling capacity than other common legumes. The dehulled samples contained 303.2-335.5 g(-1) protein and 46.1-53.5 g x kg(-1) lipid, and these values were higher than the respective whole seeds. The levels of macro- and microelements in both whole and dehulled seeds were comparable to those in common pulses. All germplasms had a high dietary fiber content (18-19.5%), made up of mainly insoluble dietary fiber (DF). Seed lipids were high in unsaturated fatty acids (64.7-66.9%), specifically linoleic acid (48-49%). Whole and dehulled seeds of the white variety from Salem were particularly rich in sulfur-containing amino acids with significantly higher levels of in vitro protein digestibility than the other two germplasms. All germplasms had high levels of total phenols and phytate, trypsin, and chymotrypsin inhibitor activities, but were low in tannins, saponins, and alpha-amylase inhibitor activity. Only weak hemagglutinating activity against cow erythrocytes and no hemagglutinating activity against human erythrocytes (O) was observed in all the samples. Dehulled seeds were higher in total starch, including resistant starch and oligosaccharides (with verbascose as the major fraction) than the respective whole seeds. Both whole and dehulled samples of the white variety of Salem germplasm showed significantly lower concentrations of L-dopa, nonmethylated, and methylated tetrahydroisoquinolines than the respective whole and dehulled samples of other germplasms. In general, dehulling didn't affect the overall nutritional status in any of the presently investigated samples.     

Effects of Brans from Specialty Sorghum Varieties on In Vitro Starch Digestibility of Soft and Hard Sorghum Endosperm Porridges

Brans of specialty sorghum varieties (high tannin, black, and black with tannin) were used to investigate the effects of sorghum phenolic compounds on starch digestibility of soft and hard sorghum endosperm porridges. Endosperms of varieties with the highest and lowest grain hardness index were mixed with brans of specialty sorghum varieties in the ratio of 85:15 and cooked into porridges with distilled water using a Rapid Visco Analyzer. Brans of condensed tannin containing sorghum varieties (high‐tannin and black with tannin sorghums) significantly (P < 0.05) decreased starch digestibility and estimated glycemic index (EGI) and increased resistant starch (RS) content of endosperm porridges. However, the addition of phenolic‐rich tannin‐free (mostly anthocyanins) black sorghum bran significantly (P < 0.05) increased starch digestibility and EGI but did not affect RS content of endosperm porridges. The disparate effects with black bran may, in part, result from its larger particle size and different bran structure compared with other sorghum varieties evaluated. Thus, our study showed that not only presence of phenolic compounds in the brans but also structural differences of specialty sorghum brans can have significant effects on starch digestibility.     

Protein Digestibility of Selected Legumes Treated with Ultrasound and High Hydrostatic Pressure During Soaking

In vitro protein digestibility (IVPD) of lentils, chickpeas, peas, and soybeans treated with ultrasound or high hydrostatic pressure (HHP) during soaking and then heated for 30 min at 98°C was determined using the three-enzyme method (trypsin, chymotrypsin, and peptidase). The IVPD of raw legumes ranged from 72% for soybeans to 83% for dry green peas. The increase in the IVPD after soaking was observed in lentils but not in other legumes. Heating increased the IVPD of the tested legumes by 2–13%. While the effects of applying ultrasound or HHP on IVPD of legumes were mostly inconsistent or insignificant, soaking under HHP for 1 hr and subsequent heating at 98°C for 30 min increased IVPD of legumes. Compared with raw legumes, the soluble protein concentrates exhibited 2–4% higher IVPD, while insoluble proteins exhibited 0.2–1.5% lower IVPD. SDS-PAGE of legume proteins before enzyme digestion exhibited 8–18 protein bands from 20 kDa to 100 kDa representing isolated soluble proteins and from 20 kDa to 100 kDa representing insoluble proteins. After enzyme digestion, soluble proteins exhibited 2–6 minor protein bands with molecular weights <30 kDa, while insoluble proteins of lentils, chickpeas, and peas exhibited one major protein band at ≈52 kDa and two or three minor protein bands with molecular weights <30 kDa. The major insoluble proteins observed as electrophoresis bands after enzyme digestion may be responsible for the reduced protein digestibility of legume proteins.     

外源物质浸种对黄瓜陈种子萌发效应的影响

为提高老化种子的生活力和利用率，有效利用黄瓜种子，给黄瓜陈种子在生产中的应用提供数据支撑。以贮存11 a的黄瓜品种甘丰11号种子为材料，采用培养皿发芽法，研究不同外源物质CaCl2、KH2PO4、KNO3、SA、ZnSO4浸种对黄瓜陈种子萌发的影响。结果表明，5种不同浓度的药剂均能不同程度提高黄瓜种子的发芽率，以0.175 mg/L的CaCl2溶液浸种对黄瓜陈种子萌发的促进作用最显著，其发芽率为(91.67±1.66)%、发芽势为(87.90±1.40)%、发芽指数为53.63±2.15，较对照只加入清水处理分别提高31.58%、56.96%、69.37%，各处理间差异达到显著水平(P ＜ 0.05)。生产中可以选用0.175 mg/L的CaCl2溶液浸泡处理黄瓜陈种子。     

Determination of Pea Proteinase Inhibitors Using ELISA Based on Monoclonal Antibodies

Abstract

An immunoassay method for analysis of trypsin and chymotrypsin inhibitor activity in seeds from different pea cultivars has been developed. This method is fast, cheap and well suited for screening of large numbers of seed samples. The technique is based on enzyme linked immunoassay (ELISA) using monoclonal antibodies produced against pea (Pisum sativum L.) proteintype trypsin inhibitors (PPI). The results obtained by ELISA have been compared with results achieved by using traditional enzymatic analyses for determination of both trypsin and chymotrypsin inhibitor contents, and these methods showed good agreement. Great differences in PPI levels have been found between various pea cultivars grown in Finland and Denmark, and these differences comprised both the total amount of PPI and the relative composition of individual PPI. Several proteins occurring in pea exhibited inhibitor activity, and at least 10 PPI inhibitors with p/ values 4.9–7.8 were detected. Pea cultivars with low PPI levels had a PPI composition different from the PPI composition found in cultivars with high PPI levels.     

花生种子自然老化对品质及发芽的影响

为解析花生种子自然老化过程中品质及发芽特性的变化特征,本研究以6个花生品种(系)为试材,通过测定种子发芽率、发芽势、氯化三苯基四氮唑(TTC)还原量、电导率等指标对老化花生种子的品质和发芽活力进行综合评价。结果表明,随着种子老化程度加深,不同品种(系)花生种子的5个发芽指标(发芽率、发芽势、发芽指数、活力指数和生长量)均表现为显著下降趋势(P<0.05);花生种子的活力指数与TTC还原量呈相同的下降趋势,而电导率则呈上升趋势;除了亚油酸以外,其余4个花生品质指标,包括油酸、油亚比(O/L)含油量和粗蛋白,总体呈下降趋势,自然老化对花生品质及发芽特性均产生负向影响。本研究通过对自然老化种子中多个指标进行评价,为确定和探究不同花生品种的存储条件及代谢途径奠定一定的理论基础。     

两株PGPR对豇豆苗期生长及土著细菌群落的影响

以扬豇40为材料,研究了植物根际促生菌Pseudomonas chlororaphis RA6和Bacillus pumilus WP8对豇豆种子出苗及幼苗生长的作用,评价浸种及拌土处理的差异,揭示一段时间内,两株植物根际促生菌（PGPR）在土壤中的行为特征及其对土著细菌群落结构的影响。结果表明：PGPR对豇豆的促生作用因接种方式、接种量的不同而不同。WP8、RA6浸种处理的出苗率分别比对照提高14.29%和9.52%（P〈0.05）;15 d时的株高分别比对照提高14.39%和10.40%（P〈0.05）;茎叶干物重分别比对照增加19.69%和17.71%（P〈0.05）。WP8、RA6低剂量拌土处理（104cfu·g-1soil,以下简作＂低拌处理＂）各指标与对照相比,均无显著差异（P〉0.05）。WP8、RA6中剂量拌土处理（106cfu·g-1soil,以下简作＂中拌处理＂）出苗率和株高均比对照提高,但未达显著差异（P〉0.05）;茎叶干物重分别比对照增加12.71%和18.59%（P〈0.05）。WP8、RA6高剂量拌土处理（108cfu·g-1soil,以下简作＂高拌处理＂）出苗率分别比对照提高9.52%和14.29%（P〈0.05）;15 d时的株高分别比对照提高6.37%和7.64%（P〈0.05）;茎叶干物重分别比对照增加27.37%和20.43%（P〈0.05）。DGGE指纹图谱分析结果显示：各处理在15 d和45 d时,除WP8浸种处理外,其余土壤微生物群落多样性和对照均已发生明显变化,随时间推延,RA6菌株在土壤中优势地位更趋明显,表现在45 d时仍可明显检测到;WP8在土壤中存活时间不长,但拌土处理改变了土著细菌的群落结构。推测WP8的促生作用很可能与土著微生物群落的变化有关。     

保水剂在节水农业中的应用

本文研究了保水剂包膜涂层对大豆、小麦、绿豆等作物种子萌发成苗及保水剂蘸根对葡萄苗、山茱萸苗移栽成活率的影响，结果表明；1%保水剂包膜涂层可促进大豆、绿豆等豆类种子出苗率，使其出苗早，苗齐苗壮，抗旱能力增强，而对小麦玉米等淀粉种子的出苗无明显作用；低浓度的保水剂蘸根可提高苗木的成活率，促进其生长，增强抗旱能力，而高浓度的保水剂蘸根则降低苗木成活率，生长下降。     

Effect of a Bowman-Birk proteinase inhibitor from Phaseolus coccineus on Hypothenemus hampei gut proteinases in vitro

The coffee berry borer, Hypothenemus hampei (Ferrari), is an important devastating coffee pest worldwide. Both trypsin and chymotrypsin enzyme activities from H. hampei larval midgut can be inactivated by proteinaceous enzyme-inhibitors. A serine proteinase inhibitor belonging to the Bowman-Birk class was purified from a wild accession of Phaseolus coccineus L. seeds. The inhibitor (PcBBI1) is a cysteine-rich protein that is heat-stable at alkaline pH. MALDI-TOF/MS analysis showed that PcBBI1 occurs in seeds as a monomer (8689 Da) or dimer (17,378 Da). Using in vitro inhibition assays, it was found that PcBBI1 has a high inhibitory activity against H. hampei trypsin-like enzymes, bovine pancreatic chymotrypsin, and trypsin. According to this, PcBBI1 could be a promising tool to make genetically modified coffee with resistance to coffee berry borer.     

胆碱脂肪酸/氨基酸对PEG模拟干旱胁迫下玉米萌发的影响

为探究秸秆预处理过程中产生的胆碱类离子液体残液对干旱胁迫下玉米种子萌发的影响,以典型农作物玉米(Zea mays L.)为研究对象,使用13%聚乙二醇-6000(PEG)模拟干旱胁迫,以种子萌发参数、根芽长、种胚抗氧化酶活性为指标,研究200 mg·L^-1胆碱脂肪酸离子液体(胆碱己二酸、胆碱辛二酸)和胆碱氨基酸离子液体(胆碱缬氨酸、胆碱苏氨酸、胆碱天冬氨酸、胆碱天冬酰胺)浸种处理对PEG模拟干旱胁迫下玉米种子萌发的影响。结果表明,PEG模拟干旱胁迫下,胆碱己二酸、胆碱辛二酸浸种处理显著提高了玉米种子的发芽指数,胆碱天冬氨酸、胆碱天冬酰胺浸种处理显著提高了种子的发芽势。另外,胆碱类离子液体浸种均促进了干旱胁迫下玉米根芽的生长,其中胆碱苏氨酸浸种处理下芽长增加最显著,增加48.2%;胆碱天冬氨酸浸种处理下根长增加最显著,增加26.7%。在PEG模拟干旱胁迫条件下,不同胆碱脂肪酸和胆碱氨基酸浸种处理提高了种胚中过氧化物酶(POD)和过氧化氢酶(CAT)活性,且丙二醛(MDA)和过氧化氢(H₂O₂)含量均显著下降。综上,胆碱类离子液体浸种处理可能通过提高PEG模拟干旱胁迫下玉米种胚的抗氧化酶活性,降低MDA和H₂O₂含量,缓解氧化胁迫,促进PEG模拟干旱胁迫下玉米种子的萌发与萌发后根芽的生长。胆碱类离子液体有望作为作物生长调控物质,这为胆碱离子液体残液的利用提供了可行的途径。     

Immunochemical and structural analysis of pepsin-digested egg white ovomucoid

Ovomucoid, an egg protein comprising approximately 10% egg white, was digested using the enzyme pepsin, and fragments were isolated by anion-exchange and reverse phase HPLC. Four distinct fragments were identified by analysis with SDS-PAGE, including three large fragments with molecular weights of around 24, 18, and 14 kDa. N- and C-terminal and amino acid sequencing analyses identified the fragments as V134-C186 (domain 3), V21-A133, and A1-A133 (domain 1+2). Further separation and sequencing of the fraction composed of small peptides, to determine their exact makeup and location in the protein, remained to be carried out and identified a peptide G51-Y73. All four fragments showed IgE-binding activity, as measured by ELISA, using human sera from egg-allergic individuals. Little change in the digestibility of ovomucoid by trypsin and chymotrypsin was observed following digestion with pepsin, indicating that pepsin-digested ovomucoid retains its trypsin (protease) inhibitor activities. Reduced carboxymethylated ovomucoid was prepared, and digestion with pepsin produced significantly more peptides than did the digestion of the native ovomucoid, indicating that the disulfide bonds play a significant role in the digestive resistance of ovomucoid. The reduction of ovomucoid enhanced its digestibility and lower allergenicity of the protein.     

Promoting deep-sowing germinability of corn (Zea mays) by seed soaking with gibberellic acid

The effects of seed soaking with gibberellic acid (GA₃) on germinability of conventional corn variety ‘Nongda 108’ and super sweet corn variety ‘Chaotian 3’ were investigated under deep-sowing condition. GA₃ soaking significantly improved seed germination and mesocotyl elongation of both varieties under 10 or 6 cm sowing depth. The most significant promotion occurred at 0.175 g L^?1 GA₃ in ‘Nongda 108’ and 0.035 g L^?1 GA₃ in ‘Chaotian 3’. To further illustrate the physiological explanations, seed respiration was estimated from dehydrogenase activity test and oxygen-sensing test. Dehydrogenase activities of both varieties were dramatically promoted after GA₃ soaking. Compared with water soaking, the dehydrogenase activity in 0.175 g L^?1 GA₃-soaked seeds of ‘Nongda 108’ and 0.035 g L^?1 GA₃-soaked ones of ‘Chaotian 3’ was increased by 15.4% and 78.8%, respectively. Oxygen-sensing test showed that increased metabolism time (IMT) critical oxygen pressure (COP) and relative germination time (RGT) were decreased while oxygen metabolism rate (OMR) and relative germination rate (RGR) were increased in GA₃-soaked seeds, suggesting that exogenous GA-accelerated seed respiration. Our results suggested that seed soaking with exogenous GA₃ was a simple and practicable method to improve deep-sowing tolerance during corn seed germination, and the significant promotions were attributed to vigorous respiratory metabolism.     

Ca2+对苯丙烯酸胁迫下黄瓜种子萌发特性的影响

以黄瓜（Cucumis Sativus L.）种子为材料,研究钙浸种对苯丙烯酸（CA）胁迫下黄瓜种子萌发的影响及其机理。结果表明,CA对黄瓜种子萌发有明显的抑制作用,且抑制程度随CA浓度（0.25~1.0mmol·L-1）的增加而提高。CA胁迫下,黄瓜种子的发芽势、发芽率下降,膜结构受损,透性增大,呼吸速率、α-淀粉酶和蛋白酶活性降低,淀粉、蛋白质消耗率下降,钙浸种（500 mg·L-1CaCl2）可以缓解CA对种子萌发的抑制作用,表现为发芽率提高,膜透性降低,呼吸速率、α-淀粉酶、蛋白酶活性以及淀粉和蛋白质消耗率提高。     

Influence of lupin (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) germination on microbial population and biogenic amines

Microbial population and bioactive amine profile and levels of two lupin species (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) seeds as affected by germination were investigated. Microbial population increased considerably mainly in the first stage of germination (2 days), then small changes in bacterial numbers were observed up to 5 days to levels between 7.8 and 8.9 log colony-forming units/g. Microorganisms belonging to the Enterobacteriaceae family were dominant for the legumes tested. Ungerminated legume seeds contained putrescine, cadaverine, histamine, tyramine, spermidine, and spermine. Bioactive amine levels found in fenugreek seeds were between 3- and 4-fold higher than those found in lupin seeds. The highest total amine levels were found in fenugreek seeds [162 mg/kg of dry weight (dw)], followed by L. angustifolius var. zapaton seeds (84 mg/kg of dw) and, finally, L. luteus cv. 4492 (46 mg/kg of dw) seeds. The concentration of individual amines showed a gradual rising trend during the germination period in all tested sprouts, reaching levels >3 times higher than those found in ungerminated seeds. After 5 days of germination, the fenugreek sprouts contained the highest amount of total bioactive amines. Tyramine was the predominant amine in both lupin varieties, whereas cadaverine was the main bioactive amine detected in fenugreek. The results of this work thus indicated that microbial population and biogenic amine levels in the studied lupin and fenugreek sprouts are not a risk for healthy consumers or for individuals with restricted activity of detoxification enzymes.     

Relative abundance and inhibitory distribution of protease inhibitors in potato juice from cv. Elkana.

Protease inhibitors from potato juice of cv. Elkana were purified and quantified. The protease inhibitors represent ca. 50% of the total soluble proteins in potato juice. The protease inhibitors were classified into seven different families: potato inhibitor I (PI-1), potato inhibitor II (PI-2), potato cysteine protease inhibitor (PCPI), potato aspartate protease inhibitor (PAPI), potato Kunitz-type protease inhibitor (PKPI), potato carboxypeptidase inhibitor (PCI), and "other serine protease inhibitors". The most abundant families were the PI-2 and PCPI families, representing 22 and 12% of all proteins in potato juice, respectively. Potato protease inhibitors show a broad spectrum of enzyme inhibition. All the families (except PCI) inhibited trypsin and/or chymotrypsin. PI-2 isoforms exhibit 82 and 50% of the total trypsin and chymotrypsin inhibiting activity, respectively. A strong variation within the latter activities was shown within one family and between protease inhibitor families.     

Commercial Phaseolus vulgaris extract (starch stopper) increases ileal endogenous amino acid and crude protein losses in the growing rat

The effect of a commercial Phaseolus vulgaris extract (PVE, starch stopper) on ileal and fecal endogenous protein losses was studied. Growing rats were fed for 14 days a protein-free diet containing PVE at a nutritional concentration of 0% (PF1), 0.4% (PF2), or 1.1% PVE (PF3) or 1.1% autoclaved PVE (PF4). An indigestible marker (TiO(2)) was included in each diet. Ileal endogenous amino acid (AA) losses were significantly higher (P < 0.05) in PF3 (20% higher than in PF1), except for Pro, Gly, Ala, and His. Endogenous ileal N losses were 22% higher in PF3 than in PF1. Endogenous fecal AA and N losses were all significantly higher (P < 0.05) in PF3. Starch digestibility ( approximately 100%), food intake (single daily meal, d10-23), and body weight loss were not significantly different among the groups. PVE, at 1.1% of the diet, not only was ineffective in reducing starch digestibility but also led to increased ileal endogenous N losses, possibly due to the antinutritional factors (trypsin inhibitor, lectin) present in the PVE.     

Thiamine (vitamin B1) deficiency in germinating seeds of Phaseolus vulgaris L. exposed to soaking injury

Exogenous application of thiamine (vitamin B1) during imbibition improved germination and seedling development of bean (Phaseolus vulgaris L. cv. Lasso) seeds, which were exposed to soaking injury by submergence. Leaching of the vitamin into the incubation medium was not increased in submerged seeds. However, translocation of the thiamine reserves from the cotyledons to the seedling axis was reduced in response to soaking injury. After exogenous application of free thiamine to the seeds, thiaminedi-phosphate (TDP), which is the physiologically active coenzyme form of thiamine, accumulated in the seedling axis of submerged seeds, suggesting an increased demand for thiamine-dependent metabolic reactions in these tissues. Limited oxygen supply of the seeds during the soaking period induces a shift from respiration to fermentation of carbohydrates. Neither thiamine-dependent ethanolic fermentation, nor ATP production or adenylate energy charge (AEC) of the seedling axis were affected by exogenous thiamine application, suggesting that there is no limitation of thiamine-dependent reactions in the energy metabolism of the seedlings. Thus the physiological mechanisms improving germination and seedling development of submerged seeds in response to thiamine seed treatment are still not clear.