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Effects of water level fluctuation on the growth of Nelumbo nucifera Gaertn. in Lake Kasumigaura, Japan
Author(s) -
Nohara Seiichi,
Tsuchiya Takayoshi
Publication year - 1990
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02346994
Subject(s) - petiole (insect anatomy) , biomass (ecology) , typhoon , leaf area index , environmental science , nelumbo nucifera , flooding (psychology) , botany , biology , horticulture , agronomy , oceanography , geology , lotus , hymenoptera , psychology , psychotherapist
Investigations were made of the growth of Nelumbo nucifera , an aquatic higher plant, in a natural stand in Lake Kasumigaura. A rise of 1.0 m in the water level after a typhoon in August 1986 caused a subsequent decrease in biomass of N. nucifera from the maximum of 291 g d.w. m −2 in July to a minimum of 75 g d.w. m −2 . The biomass recovered thereafter in shallower regions. The underground biomass in October tended to increase toward the shore. The total leaf area index (LAI) is the sum of LAI of floating leaves and emergent leaves. The maximum total LAI was 1.3 and 2.8 m 2 m −2 in 1986 and 1987, respectively. LAI of floating leaves did not exceed 1 m 2 m −2 . The elongation rates of the petiole of floating and emergent leaves just after unrolling were 2.6 and 3.4 cm day −1 , respectively. The sudden rise in water level (25 cm day −1 ) after the typhoon in August 1986 caused drowning and subsequent decomposition of the mature leaves. Only the young leaves were able to elongate, allowing their laminae to reach the water surface. The fluctuation in water level, characterized by the amplitude and duration of flooding and the time of flooding in the life cycle, is an important factor determining the growth and survival of N. nucifera in Lake Kasumigaura.