Effect of N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) treatment of Capsicum annuum L. cv. 'Ancho St Luis' roots on plant growth characteristics

Effect of N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) treatment of Capsicum annuum L. cv. 'Ancho St Luis' roots on plant growth characteristics

2008

A:PS

This study explored the influence of N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) treatment of the roots on shoot growth and root growth, and investigated the effects of a GA3 foliar spray on reversing the growth suppression of chilli 'Ancho St Luis' shoots due to CPPU treatment of the root system. In the first experiment, six-week-old chilli seedling roots were soaked in an aqueous solution of CPPU (10 mg.C1) for two hours, transplanted into pots and grown in a glasshouse. In the second experiment, the roots of six-week-old seedlings were soaked in three concentrations (1, 5, or 10 mg.L-1) of CPPU for two hours, transplanted into pots, and grown in a glasshouse. Four weeks after CPPU treatment, the plants were sprayed with gibberellic acid (GA3) at 100 mg' L-1 as a single foliar spray. Results showed that root applied CPPU at 10 mg.L-1 significantly decreased plant height, probably by inhibiting the activity of the sub-apical region of shoot, reducing internode number and length at 2 and 4 weeks after treatment, and suppressing root growth. CPPU-treated plants also resulted in delayed flowering. Application of GA3 to shoots did not reverse CPPU effect. Therefore, CPPU applied to roots may not only block GA3 biosynthesis but also block GA3 action.

v.49(4):221-225, HORTICULTURE, ENVIRONMENT, AND BIOTECHNOLOGY

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