Paclobutrazol Applied on Cotyledonal Leaves and Quality of Cucumber, Squash, Melon and Watermelon Seedlings

Luz Llarely Cázarez Flores,Felipe Ayala Tafoya,Moisés Gilberto Yáñez Juárez,Leopoldo Partida Ruvalcaba,Teresa De Jesús Velázquez Alcaraz,Tomás Díaz Valdés,Norma Delia Zazueta Torres

doi:10.4236/as.2018.93020

Abstract

The research was done to determine the effects of paclobutrazol (PBZ) through the dose of 150 mg·L-1, on the quality of seedlings determined by the content of chlorophyll, height, leaf area, dry matter of roots and of the aerial part of cucumber, squash, melon and watermelon. Sowing of all species carried out on October 21, 2013 in polystyrene trays with 200 cavities filled with peat moss. Treatments were the doses of 150 mg of PBZ·L-1 water and the control (distilled water). The solution with PBZ and the distilled water were applied only once with manual atomizer on cotyledonal leaves by mean of 25 shots made approximately with the same force, having put physical barriers between experimental units. In the four species (cucumber, squash, melon and watermelon) the PBZ increased the chlorophyll content in 26.0%, 14.9%, 19.4% and 26.5%, respectively, compared to the control; height decreased in 24.0%, 34.7%, 16.3% and 23.4%; leaf area decreased in 40.1, 0.5, 30.4 and 16.2%; the dry matter of roots increased in 20.0%, 62.5%, 85.7% and 19.7%; whereas in cucumber the dry matter of the aerial part increased 12.3%, in squash decreased 5.3%, and in melon and watermelon increased in the respective 22.9 and 3.3%, so that the 150 mg dose of PBZ can be used to produce seedlings with higher quality for transplant.

Highlights

IntroductionThere are several technologies used as growth retardants, including paclobutrazol (PBZ), which is characterized by delaying cell division and elongation in tissues of the actively growing outbreak, without causing stem malformations or the leaves [4]
In the four species the PBZ increased the chlorophyll content in 26.0%, 14.9%, 19.4% and 26.5%, respectively, compared to the control; height decreased in 24.0%, 34.7%, 16.3% and 23.4%; leaf area decreased in 40.1, 0.5, 30.4 and 16.2%; the dry matter of roots increased in 20.0%, 62.5%, 85.7% and 19.7%; whereas in cucumber the dry matter of the aerial part increased 12.3%, in squash decreased 5.3%, and in melon and watermelon increased in the respective 22.9 and 3.3%, so that the 150 mg dose of PBZ can be used to produce seedlings with higher quality for transplant
In the chlorophyll content of cucumber leaves significant differences were detected (Tukey, 0.05), such that in those plants treated with PBZ an increase of 26% was observed with respect to the control (Table 1), while height decreased in 24% and leaf area 40.1%, compared to the respective control averages

Summary

Introduction

There are several technologies used as growth retardants, including paclobutrazol (PBZ), which is characterized by delaying cell division and elongation in tissues of the actively growing outbreak, without causing stem malformations or the leaves [4]. With said substance has been achieved to reduce shoot elongation, leaf expansion and stem diameter growth in many tree species [5], since it is an active inhibitor of gibberellic acid biosynthesis, retard the division and elongation cell, and growth in stem length of plants [6]. The retardant is absorbed passively through the leaves, stems and roots, and translocated by the xylem until the points of growth, where by inhibition of the action of gibberellin reduces cell division in the subapical part [7]

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