{"title":"Instantaneous Flooding and α-Tocopherol Content in Tuberous Roots of Sweetpotato ( Ipomoea batatas (L.) Lam.)","authors":"T. Eguchi, Yuji Ito, S. Yoshida","doi":"10.2525/ECB.53.13","DOIUrl":null,"url":null,"abstract":"In a previous study (Eguchi et al., 2012), tuberous root growth and antioxidant contents of two sweetpotato Ipomoea batatas (L.) Lam.) cultivars were examined using two different irrigation schemes: periodic surface-irrigation and continuous sub-irrigation. Although no apparent differences in tuberous root development were observed between the two irrigation methods, the content of tocopherol in the surface-irrigated tuberous root was significantly higher for both the cultivars. We speculated that the periodical wetting of the tuberous root surface might increase the content of the antioxidant, -tocopherol. The inner portion of bulky plant tissues such as tuberous roots can become hypoxic because they are located at sites remote from the sites of oxygen entry (Geigenberger, 2003). Furthermore, hypoxia causes oxidative stress in plant tissue (Blokhina et al., 2003). A thin water film that covers the root surface may inhibit oxygen movement into the roots, and cause an increase in the content of the antioxidant -tocopherol, for coping with the slight oxidative stress occurring within the roots. However, there was doubt as to whether the surface-irrigated water completely coated the tuberous roots. Small container cultivation as we previously used for sweetpotatoes (Eguchi et al., 2012) can readily apply instantaneous flooding, which perfectly covers the whole surface of the tuberous root. In the previous study, the O2 concentration around the tuberous root was maintained at approximately 21% during the cultivation period and was unaffected by irrigation because of the good gas permeability and water drainage of the root media. In that case, instantaneous flooding may not greatly disturb O2 concentrations when we use the same root media. Therefore, in this study, we performed instantaneous flooding of sweetpotato plants grown in a small container. The effects of the flooding treatments with different times and different intervals were investigated with regards to the -tocopherol contents in the tuberous roots. Electrolyte leakage from the root flesh was also measured for examination of the occurrence of physiological stress within the root.","PeriodicalId":11762,"journal":{"name":"Environmental Control in Biology","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"5","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Environmental Control in Biology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2525/ECB.53.13","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Agricultural and Biological Sciences","Score":null,"Total":0}
引用次数: 5
Abstract
In a previous study (Eguchi et al., 2012), tuberous root growth and antioxidant contents of two sweetpotato Ipomoea batatas (L.) Lam.) cultivars were examined using two different irrigation schemes: periodic surface-irrigation and continuous sub-irrigation. Although no apparent differences in tuberous root development were observed between the two irrigation methods, the content of tocopherol in the surface-irrigated tuberous root was significantly higher for both the cultivars. We speculated that the periodical wetting of the tuberous root surface might increase the content of the antioxidant, -tocopherol. The inner portion of bulky plant tissues such as tuberous roots can become hypoxic because they are located at sites remote from the sites of oxygen entry (Geigenberger, 2003). Furthermore, hypoxia causes oxidative stress in plant tissue (Blokhina et al., 2003). A thin water film that covers the root surface may inhibit oxygen movement into the roots, and cause an increase in the content of the antioxidant -tocopherol, for coping with the slight oxidative stress occurring within the roots. However, there was doubt as to whether the surface-irrigated water completely coated the tuberous roots. Small container cultivation as we previously used for sweetpotatoes (Eguchi et al., 2012) can readily apply instantaneous flooding, which perfectly covers the whole surface of the tuberous root. In the previous study, the O2 concentration around the tuberous root was maintained at approximately 21% during the cultivation period and was unaffected by irrigation because of the good gas permeability and water drainage of the root media. In that case, instantaneous flooding may not greatly disturb O2 concentrations when we use the same root media. Therefore, in this study, we performed instantaneous flooding of sweetpotato plants grown in a small container. The effects of the flooding treatments with different times and different intervals were investigated with regards to the -tocopherol contents in the tuberous roots. Electrolyte leakage from the root flesh was also measured for examination of the occurrence of physiological stress within the root.
在之前的一项研究中(Eguchi et al., 2012),两种甘薯Ipomoea batatas (L.)的块根生长和抗氧化剂含量采用两种不同的灌溉方案:定期地表灌溉和连续次灌溉。虽然两种灌溉方式对块根发育无明显影响,但地表灌溉的块根中生育酚含量显著高于地表灌溉的块根。我们推测,块根表面的周期性湿润可能会增加抗氧化剂-生育酚的含量。块茎根等大型植物组织的内部部分可能会缺氧,因为它们位于远离氧气进入部位的位置(Geigenberger, 2003)。此外,缺氧导致植物组织氧化应激(Blokhina et al., 2003)。覆盖在根表面的一层薄薄的水膜可能会抑制氧气进入根内,并导致抗氧化剂-生育酚含量的增加,以应对根内发生的轻微氧化应激。然而,地表水是否完全覆盖了块根还存在疑问。我们以前用于甘薯的小容器栽培(Eguchi等人,2012年)可以很容易地应用瞬时洪水,完美地覆盖了块根的整个表面。在之前的研究中,由于块根介质具有良好的透气性和排水性,在栽培期间,块根周围的O2浓度保持在21%左右,不受灌溉的影响。在这种情况下,当我们使用相同的根介质时,瞬时淹水可能不会对O2浓度产生很大的干扰。因此,在这项研究中,我们对种植在一个小容器中的甘薯植物进行了瞬时淹水。研究了不同时间、不同时间间隔淹水处理对块根-生育酚含量的影响。还测量了根肉的电解质泄漏,以检查根内生理应激的发生。