개구리밥 휴면구조 잠아의 구조적 특성
Turion as Dormant Structure in Spirodela polyrhiza
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참고문헌
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초록
Hydrophytes such as Spirodela polyrhiza form dormant turions to withstand cold winters. The turion is an anatomically distinct structure from which a vegetative frond arises later during germination. The turions sink to the bottom of the pond when temperatures drop and remain there throughout the winter. In the spring, they float to the surface and germinate into a new frond from the turion primordium. Unlike fronds, turions are known to possess small aerenchyma, starch grains, and relatively dense cytoplasm. These features allow the turions to survive the cold winter season at the bottom of the pond. Spirodela polyrhiza has been investigated previously to a great extent, especially in its physiological, biochemical and ecological attributes. However, a little is known about the structural features of the frond and turion during turion development. Thus, the aim of the present study was to reveal the structural characteristics of the frond and turion with regard to tissue differentiation, aerenchyma development, starch distribution, and ultrastructure, with the use of electron microscopy. A moderate degree of mesophyll tissue differentiation was found in the frond, whereas the turion did not exhibit such differentiation. Within the frond tissue, approximately 37~45% of the cellular volume was occupied by a large aerenchyma, but only 9~15% was taken up by the aerenchyma in the turion. The turion cells, especially those of the turion primordium, were derived from frond cells, and contained cytoplasm. Their cytoplasm was densely packed with plastids, mitochondria, endoplasmic reticulum, Golgi bodies, and microtubules. Plasmodesmata were also well developed within these cells. The most striking feature observed was the distribution of starch grains within the plastids of turion cells. Before the turion sank to the bottom of the pond, a considerable amount of starch accumulated in the plastid stroma. The starch grains dissolved when temperatures rose in the spring, and this promptly provided the nutrients which the primordium needed for turion germination. The turion therefore, was an appropriate dormant structure for free-floating, reduced hydrophytes like Spirodela polyhriza due to its small aerenchyma and large starch grains that aided in the purpose of sinking below the surface of the water to survive cold winters. The new fronds that arose from such turions grew rapidly in the spring, beginning the new life cycle.
Abstract
Hydrophytes such as Spirodela polyrhiza form dormant turions to withstand cold winters. The turion is an anatomically distinct structure from which a vegetative frond arises later during germination. The turions sink to the bottom of the pond when temperatures drop and remain there throughout the winter. In the spring, they float to the surface and germinate into a new frond from the turion primordium. Unlike fronds, turions are known to possess small aerenchyma, starch grains, and relatively dense cytoplasm. These features allow the turions to survive the cold winter season at the bottom of the pond. Spirodela polyrhiza has been investigated previously to a great extent, especially in its physiological, biochemical and ecological attributes. However, a little is known about the structural features of the frond and turion during turion development. Thus, the aim of the present study was to reveal the structural characteristics of the frond and turion with regard to tissue differentiation, aerenchyma development, starch distribution, and ultrastructure, with the use of electron microscopy. A moderate degree of mesophyll tissue differentiation was found in the frond, whereas the turion did not exhibit such differentiation. Within the frond tissue, approximately 37~45% of the cellular volume was occupied by a large aerenchyma, but only 9~15% was taken up by the aerenchyma in the turion. The turion cells, especially those of the turion primordium, were derived from frond cells, and contained cytoplasm. Their cytoplasm was densely packed with plastids, mitochondria, endoplasmic reticulum, Golgi bodies, and microtubules. Plasmodesmata were also well developed within these cells. The most striking feature observed was the distribution of starch grains within the plastids of turion cells. Before the turion sank to the bottom of the pond, a considerable amount of starch accumulated in the plastid stroma. The starch grains dissolved when temperatures rose in the spring, and this promptly provided the nutrients which the primordium needed for turion germination. The turion therefore, was an appropriate dormant structure for free-floating, reduced hydrophytes like Spirodela polyhriza due to its small aerenchyma and large starch grains that aided in the purpose of sinking below the surface of the water to survive cold winters. The new fronds that arose from such turions grew rapidly in the spring, beginning the new life cycle.
참고문헌 (24)
- Appenroth KJ, "No photoperiodoc control of the formation of turions in eight clones of Spirodela polyrhiza", J Plant Physiol, 160, pp.1329~1334 (2003)
- Appenroth KJ, "Photophysiology of turion germination in Spirodela polyrhiza (L.) Schieiden XI. structural changes during red light induced responses", J Plant Physiol, 141, pp.583~588 (1993)
- Chaloupková K, "The abscisic acid induction of a novel peroxidase is antagonized by cytokinin in Spirodela polyrhiza (L.)", Plant Physiol, 105, pp.497~507 (1994)
- Fahn A, "Plant Anatomy", pp.10~49 (1990), Pergamon Press
- Harada T, "Starch degradation and sucrose metabolism during anaerobic growth of pondweed (Potamogeton distinctus A. Benn", turions. Plant and Soil, 253, pp.125~135 (2003), 125-135
- 지상용, "부유부엽성 생이가래 모용의 구조적 특징", 한국전자현미경학회지, 32(4), pp.3~327 (2002), 한국현미경학회
- Jian Y, "Control of turion germination in Potamogeton crispus", Aquat Bot, 75, pp.59~69 (2003)
- Kim KA, "Structural aspect of the reduced free-floating hydrophyte, Spirodela polyrhiza", Kor J Electron Microsc, 30, pp.233~240 (2000)
- Landolt E, "Biosystematic Investigations in the Family of Duckweeds (Lemnaceae); Vol. 2", The family of Lemnaceae a monographic study, 1, pp.566~ (1986)
- Lee KB, "Plant Morphology", Life Science, pp.91~ (2004)
- Lee SM, "Science of Hydrophytes", pp.76~85 (2005), Chonnam University Publishing
- Lee YN, "Illustrated Flora of Korea Plant Biology", pp.1054~ (1996), Kyohak Publishing Co.
- Lemon GD, "Shoot morphology and organogenesis of the aquatic floating fern Salvinia molesta. D. S. Mitchell, examined with the aid of laser scanning confocal microscopy", Intl J Plant Sci, 158, pp.693~703 (1997)
- Ley S, "Carbohydrate metabolism as a possible physiological modulator of dormancy in turion of Spirodela polyrhiza (L.) Schlieden", Plant Sci, 129, pp.1~7 (1997)
- Lim DB, "Plant Morphology", pp.493~510 (1992), Woosung Publishing
- Mauseth JD, "Plant Anatomy", pp.415~437 (1988), The Benjamin Cummings Publishing Co.
- Mclaly CL, "The effect pH on the population growth of three species of duckweed: Spirodela polyrhiza, Lemna minor and Wolffia arrhiza", Freshwater Biol, 6, pp.125~136 (1976)
- Newton RJ, "Turion formation and germination in Spirodela polyrhiza", Amer J Bot, 65, pp.421~428 (1978)
- Reimann R, "The binding of α-amylase to starch plays a decisive role in the initiation of storage starch degradation in turions of Spirodela ployrhiza", Physiol Plant, 129, pp.334~341 (2007)
- Sculthorpe CD, "The Biology of Aquatic Vascular Plants", pp.198~208 (1967), Edward Arnold Ltd
- Sibaski T, "Heterogeneity of dormancy in the turion of Spiodela polyrhiza", Plant Cell Physiol, 20, pp.563~571 (1979)
- Smart CC, "Abscisic-acid-induced turion formation in Spirodela polyrhiza L. II. Ultrastructure of the turion; a stereological analysis", Plant Cell Environ, 6, pp.515~522 (1983)
- Tobiessen P, "Temperature and light effects on the growth of Potamogeton crispus in Collins Lake, New York State", J Bot, 62, pp.2822~2826 (1984)
- Weber JA, "The cause of sinking and floating in turion of Myriophyllum verticillatum", Aquat Bot, 83, pp.219~226 (2005)