Overcoming seed dormancy using gibberellic acid and the performance of young Syagrus coronata plants under severe drought stress and recovery

Published Date

December 2015, Vol.97:278–286, doi:10.1016/j.plaphy.2015.10.008

Research article

Title 

Overcoming seed dormancy using gibberellic acid and the performance of young Syagrus coronataplants under severe drought stress and recovery

• Author 

• Maria J. Medeiros ^a
• Marciel T. Oliveira ^a
• Lilia Willadino ^b
• Mauro G. Santos ^a,,

• aLaboratório de Ecofisiologia Vegetal, Departamento de Botânica, Universidade Federal de Pernambuco, 50670-901, Recife-PE, Brazil
• bLaboratório de Cultura de Tecidos Vegetais, Departamento de Biologia, Universidade Federal Rural de Pernambuco, 52171-900, Recife-PE, Brazil

Received 21 April 2015. Revised 24 September 2015. Accepted 5 October 2015. Available online 9 October 2015.

Highlights

• •
  Syagrus coronata seeds have physiological and physical dormancy.
• •
  Gibberellic acid application can break the dormancy of S. coronata seeds.
• •
  Plants leaves are able to tolerate severe drought stress remained evergreen.
• •
  The leaves have a high photosynthetic rate even under water deficit.
• •
  The diversity of drought tolerance mechanisms allows the resilience of this species.

Abstract

Syagrus coronata, a native palm tree of the Brazilian semi-arid region, exhibits low germinability due to seed dormancy. This study aimed to increase the germinability, analyze the morphology of seedlings and evaluate the performance of young plants under a water deficit. We used immersion in water and gibberellic acid (GA₃) as pyrene (seed with endocarp) pre-germination treatments, and we analyzed the water relations, gas exchange, chlorophyll fluorescence and carbon balance components of young plants under drought and rehydration conditions. The immersion of pyrenes in 0.3 mM GA₃ solution for 24 h enhanced the emergence and survival of plants and the emergence rate index. The germination of S. coronata is of the remote tubular type, and seedling growth originates with the protrusion of the cotyledon petiole, followed by the subsequent emergence of the root, leaf sheaths and eophyll. The plants exhibited high tolerance to no irrigation for 37 days, which was attributed to strong stomatal control, a higher proportion of energy dissipation and a higher content of photoprotective pigments. Despite the reduced stomatal conductance (regardless of soil water availability), the photosynthetic rate remained high throughout the day, which indicated a low correlation between these two parameters. After rehydration, we observed that both the leaf water content and photosynthesis recovered, which showed an absence of irreversible damage of the photosynthetic apparatus. The use of 0.3 mM GA₃ is recommended as a treatment for overcoming seed dormancy in this species. Young S. coronata plants showed high tolerance during drought and resilience after rehydration by adjusting their leaf metabolism, which could explain the endemism of this species in semi-arid regions and its ability to remain evergreen throughout the year. Furthermore, with high photosynthetic rate in the most favorable time of day, even under drought stress.

Keywords

• Chlorophyll fluorescence
• Evergreen species
• Gas exchange
• Germinability
• Palm tree

---

Fig. 1.

Fig. 2.

Fig. 3.

 Table 1

Table 1.

Fig. 4.

Fig. 5.

 Table 2

Table 2.

• ∗ 
  Corresponding author.

For further details log on website :
http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=-1020886970&_sort=v&_st=17&view=c&_origin=related_art&panel=citeRelatedArt&_mlktType=Journal&md5=0159008b77e097f6363bea77a447ea56&searchtype=a