Response of the growth and N and P nutrition to mitigating and optimization fertilization with plant growth regulators in lettuce.

摘要

To alleviate nitrate contamination of vegetables and reduce fertilizer use without damaging yield, effects of 15 combinations of plant growth regulators (PGR) on growth and nutrient uptake of lettuces grown in pots with a half rate of N-P-K (hNPK) fertilizer were studied. Biomass of most PGR-treated plants was similar to that of the full rate of NPK (fNPK) treatment. Compared with hNPK, dry wt. was significantly increased (14.4-16.2%) when treated with 3 muM indole 3-acetic acid (IAA), 2 muM 6-benzyl aminopurine (BA) and 150 muM vitamin B₁ (VB₁), 6 muM IAA, 1 muM BA, 0.5 muM gibberellic acid-3 (GA3) and 150 muM VB₁, and 6 muM IAA, 2 muM BA, 0.25 muM GA3 and 150 muM vitamin C (Vc). N and P contents increased significantly (by 14.0-35.2 and 17.1-57.9%, respectively) in most PGR treatments with hNPK. PGR treatment with 6 muM IAA, 2 muM BA, 0.25 muM GA3 and 150 muM Vc significantly increased P by 13.0% compared with fNPK. Nitrate content of PGR treated lettuce was significantly reduced by 11.1-36.0 and 33.6-52.1% compared with hNPK and fNPK, respectively. Therefore, it is suggested that combining PGR with hNPK fertilizers could simultaneously maintain high production, reduce fertilizer use and improve vegetable quality.