Journal of Taiwan Agricultural Research

Author:San-Tai Wang, Shen-Lin Lin, Woo-Nang Chang'and Ch-Hsiung Hsiao

Abstract:

The nitrate-N content were determined for 27 and 24 lettuce cultivars grown hydroponically in a nutrient solution containing 15mM NOs-N and 6mM N03-N,respectively. The hydroponic systems used were a circulated one and a non-circulated one with aeration, respectively. Cultivar's differences existed in plant fresh weight and NOs-N content. Cultivars giving higher yields than others were R8 (CHING YEH KAI LIANG WO CHU) , R24 (YUAN WO CHU) , R37 (PAI"兀J) · and R39 (KAI LIANG CHANG YEH WO CHU) . Cultivars giving consistently low yields were S25 (CHIEN YEH WO CHU) , R27 (PETO WO CHU) , R36 (N0 .3 WO CHU) . S40 (TA YEH CHIEN WO CHU) , S41 (WO CHU) and R44 (PAI WU) . Cultivars with high nitrate content were R8 (CHING YEH KAI LIANG WO CHU) , R12 (PAI WU) , R13 (WO CHU) and R43 (HUANG WO) . Cultivars giving low nitrate were S3 (CHIEN YEH WO CHU) , Rl4 (TA HSIN WO CHU) , R24 ( YUAN WO CHU) , S25 (CHIEN YEH WO CHU) , R37 (PAI WU) and R42 (WO CHU) . Nitrate content on fresh weight basis exceeded 2,500ng/kg (summer safety standard for Holland) but not 4,500 mg per kg (winter safety standard for Holland) in cultivars of RS (CHING YEH KAI LIANG WO CHU) , Rll (PAI FEN) , R12 (PAI WU) , R13 (WO CHU) , S20 (HSIAO CHIEN YEH E TSAI) and R30 (SHIN HSIN WO CHU) .

Key words:Lettuce, Nitrate content, Cultivar.

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