Responses of Foreign GA3 Application on Seedling Growth of Castor Bean (Ricinus communis L.) under Salinity Stress Conditions

Xiurong Jiao,Guisheng Zhou,Wenfang Zhi,Guijuan Liu,Guanglong Zhu,Gongneng Feng,Irshad Ahmad,Nimir Eltyb Ahmed Nimir

doi:10.3390/agronomy9060274

Xiurong Jiao, Guisheng Zhou + Show 6 more

Open Access

https://doi.org/10.3390/agronomy9060274

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Abstract

Castor bean (Ricinus communis L.), a promising bioenergy crop, is readily planted in marginal lands like saline soils. A controlled experiment was conducted to explore the possibility of using gibberellic acid (GA3) as a promoter for caster bean grown under NaCl conditions and to try to determine the most appropriate concentration of GA3 for seedling growth. The seeds of salt-tolerant cultivar Zibi 5 were firstly soaked with 0, 200, 250, and 300 µM GA3 for 12 h and then cultured with 1/2 Hoagland solution containing 0, 50, and 100 mM NaCl in pots filled with sand. Plant height, stem diameter, leaf area, dry mater of each organ, activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), soluble protein, and proline content in the leaves were examined. Plant height and stem diameter, SOD, and POD activity was significantly highest in the treatment of 250 µM GA3 under salt concentration of 50 mM NaCl among all the testing days; protein content was highest when GA3 concentration was 250 µM under 100 mM NaCl treatment. This indicated that caster bean seed soaking with 250 µM GA3 could be the most suitable concentration for promoting seedling growth of caster bean, improving their stress resistance.

Highlights

Castor bean (Ricinus communis L.) is an ideal oilseed crop because of its high seed oil content, unique fatty acid composition (900 g kg−1 of ricinoleic acid) [1], and can be successfully mixed with petroleum diesel to reduce air pollution [2]
GA3 with 25.33 and 27.74 cm on 20 d and 30 d, respectively, and lowest in the treatment with salt concentration of 100 mM NaCl and 300 μM GA3 (14.72, 16.93, and 20.51, respectively) (Table 1). It seems that the promotion effects of GA3 at 250 μM on plant height was much better than other GA3 concentrations under all the salinity treatments
Caster bean seed soaked with 250 μM GA3 significantly increased plant height, stem diameter, dry weight, and promoted the growth of leaves under all the NaCl treatments, while seed treated with other GA3 concentration had little effect on seedling growth (Table 1)

Summary

Introduction

Castor bean (Ricinus communis L.) is an ideal oilseed crop because of its high seed oil content (more than 480 g kg−1 ), unique fatty acid composition (900 g kg−1 of ricinoleic acid) [1], and can be successfully mixed with petroleum diesel to reduce air pollution [2]. Due to these characteristics, caster bean has become one of the most promising candidates for biofuel production as well as a vital industrial raw material [3]. One of the economical and efficient ways to improve and develop these saline soils is to screen salt tolerant oil crops [5]

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