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Contribution of N : P ratio and endogenous phytohormones during development of phosphorus toxicity in Brassica campestris spp. parachinensis
Author(s) -
Yang Xian,
Gu Mengmeng,
Kang Yunyan,
Feng Xinfu
Publication year - 2012
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201100237
Subject(s) - brassica , phosphorus , gibberellin , stalk , chemistry , horticulture , nitrogen , ethylene , potassium , anthocyanin , epidermis (zoology) , biology , botany , zoology , biochemistry , organic chemistry , catalysis , anatomy
Agricultural practices may lead to excessive phosphorus (P) accumulation in soil. The effects of excessive P on Chinese flowering cabbage ( Brassica campestris spp. parachinensis ) were investigated by exposing plants for 4 weeks in solution containing 1, 2, 3, 5, and 7 mM NaH 2 PO 4 . Phosphorus concentrations [P] greater than 3 mM produced significantly stunted growth, together with reduced appearance quality due to overaccumulation of anthocyanin in the epidermis of flower stalk. Nitrate concentrations in the flower stalk decreased with increasing solution [P]. Nitrogen (N) concentrations in the roots and potassium (K) concentrations in the leaves, stems, and roots all decreased at [P] higher than 3 mM. Increasing P supply caused great enhancement of root and stem [P], but decreased total plant and root N : P ratios. A positive linear relationship between solution [P] and anthocyanin concentration and a negative linear relationship between root N : P ratio and anthocyanin concentration were also observed. In addition, 3 to 7 mM P caused decreased levels of indole‐3‐acetic acid (IAA) and gibberellin (GA 3 ) in the leaves, but promoted ethylene production. The average gibberellin concentration was generally correlated with the plant's relative growth rates. Ethylene was negatively correlated with plant growth parameters except for the last day of the experiment. In conclusion, N : P ratio and endogenous phytohormones may be involved in the development of P toxicity in Chinese flowering cabbage plants.