Effects of submergence on growth and survival of saplings of three wetland trees differing in adaptive mechanisms for flood tolerance

Aim of study: Withstanding total submergence and reaeration following submergence is essential for the survival and establishment of wetland species. We focused on “LOES–low oxygen escape syndrome” and “LOQS–low oxygen quiescence syndrome” and compared tolerances to total submergence among wetland woody species differing in morphological adaptation to soil flooding.Area of study, materials and methods: This study examined the survival of 2-year-old saplings of Taxodium distichum (LOQS species), and Alnus japonica and Metasequoia glyptostroboides, (LOES species), during and after total submergence. Saplings were completely submerged, then de-submerged to determine trends in survival and growth.Main results: The M. glyptostroboides and A. japonica saplings could not survive prolonged submergence for more than 8 weeks, whereas saplings of T. distichum survived for over 2 years. Submerged saplings of all species showed no significant growth or modifications in morphology and anatomy under water, such as shoot elongation, adventitious root formation, and/or aerenchyma development. All T. distichum saplings that were de-submerged in the second year had the same pattern of shoot growth regardless of differences in timing and seasonality of de-submergence. Wood formation in T. distichum saplings ceased during submergence and resumed after de-submergence in spring and summer, but not in autumn.Research highlights: T. distichum saplings, which survived longer submergence periods than A. japonica and M. glyptostroboides, had physiological characteristics, such as suspension of growth and metabolism, which allowed survival of protracted total submergence (at least 2 years) when saplings were immersed during the dormant stage before leaf flushing.Keywords: Alnus japonica; Metasequoia glyptostroboides; survival rates; Taxodium distichum; total submergence.Abbreviations: LOES, low oxygen escape syndrome; LOQS, low oxygen quiescence syndrome

Effects of submergence on growth and survival of saplings of three wetland trees differing in adaptive mechanisms for flood tolerance

Aim of study: Withstanding total submergence and reaeration following submergence is essential for the survival and establishment of wetland species. We focused on “LOES–low oxygen escape syndrome” and “LOQS–low oxygen quiescence syndrome” and compared tolerances to total submergence among wetland woody species differing in morphological adaptation to soil flooding.Area of study, materials and methods: This study examined the survival of 2-year-old saplings of Taxodium distichum (LOQS species), and Alnus japonica and Metasequoia glyptostroboides, (LOES species), during and after total submergence. Saplings were completely submerged, then de-submerged to determine trends in survival and growth.Main results: The M. glyptostroboides and A. japonica saplings could not survive prolonged submergence for more than 8 weeks, whereas saplings of T. distichum survived for over 2 years. Submerged saplings of all species showed no significant growth or modifications in morphology and anatomy under water, such as shoot elongation, adventitious root formation, and/or aerenchyma development. All T. distichum saplings that were de-submerged in the second year had the same pattern of shoot growth regardless of differences in timing and seasonality of de-submergence. Wood formation in T. distichum saplings ceased during submergence and resumed after de-submergence in spring and summer, but not in autumn.Research highlights: T. distichum saplings, which survived longer submergence periods than A. japonica and M. glyptostroboides, had physiological characteristics, such as suspension of growth and metabolism, which allowed survival of protracted total submergence (at least 2 years) when saplings were immersed during the dormant stage before leaf flushing.Keywords: Alnus japonica; Metasequoia glyptostroboides; survival rates; Taxodium distichum; total submergence.Abbreviations: LOES, low oxygen escape syndrome; LOQS, low oxygen quiescence syndrome

Roles of ethylene, jasmonic acid, and salicylates in traumatic heartwood formation of Quercus serrata infected with Raffaelea quercivora

日本海側を中心として拡大しているナラ類集団枯死の被害木では，傷害心材，もしくは病理的心材と称される顕著な木部の着色減少が観察される．本稿では，最近発表されたMoungsrimuangdeeら（2011）による研究成果をもとに，ナラ菌の感染によって形成された傷害心材過程におけるエチレン，ジャスモン酸，およびさサリチル酸の役割を考察した