磷肥施用量對水耕小白菜化學成分之影響

Abstract

Effect of different phosphate nutrient concentration (0，5，10，20，40，80,160ppm-P) of water-culture medium on the quality and chemical compositions of small Pai-tsai (Brassica chinensis) had been discussed. At the 40ppm-P, the plant weights were highest, then the 80ppm-P and the 20ppm-P treatmento. The P treatment lower than 1 Oppm-P and the 160ppm-P treatment had less plant yield. The P concentration of both fresh leaf blade and petiole were increased with the phosphate concentrations. If the medium PO4-P less than 10ppm or more than 80ppm the weight ratio of petiole were decreased. The ascorbic acid, total soluble solids, water insoluble solid, titratable acidity, ash. Mg, S. Fe and Boron contents (in fresh weight basis) of the up-land part of plant were decreased both in the lowest and highest P treatment. Both in P deficient and P excess medium, plants grew worse. There were more P, Na, Mn and Cu (in blade) contents in the 160ppirj-P treated plants, but more ascorbic acid，soluble solid, acidity, water soluble carbohydrate, K, Ca, B, amino-nitrogen and dry matter in the Phosphate deficient plant. 探討水耕栽培營養液中不同磷肥施用量 0、5、10、20、40、80、160ppm-P對小白菜生育品質及化學組成分之影響。株重以40ppm-P標準施磷量爲最高，80ppm略低，其次爲20ppm，施磷量在10ppm以下或160ppm以上時，小白菜產量明顯減少。以鮮重爲計算基礎，無論是葉身或葉柄，其磷含量大致上會隨著磷肥施用量增加而增加。施隣量若少於10ppm-P 或大於80ppm-P時，葉柄佔全株亟量比會 愈形減少，即外觀葉柄較葉身爲小；植株 抗壞血酸、可溶固形物、不溶固形物、滴定酸度、灰分及鎂、硫、鐵、硼等元素含量則會隨著低施磷量的減少與高施磷量的增加而增加。磷肥不足或過剩之小白菜株重、單株葉數及單株亟雖然相近，但磷肥過剩時植體内有異常高的磷、鈉、錳、銅(葉身)等元素；而缺磷肥之植體則含有較高的乾物重、抗壞血酸、可溶固形物、可滴定酸度、水溶性醣、鉀、鈣、硼及胺基態氣含量。