ABSTRACT.
Seeds primed with 5-aminolevulinic acid mitigated temperature and drought stresses of wheat at germination and early seedling growth

Mohamed Suliman Eltyeb Suliman1, 2, Safiya Babiker Mustafa Elradi1, 2, Guisheng Zhou1, 3*, Nimir Eltyb Ahmed Nimir1, 2, Guanglong Zhu1, 3, and Adam Yousif Adam Ali1, 4
 
Drought and temperature stresses are known as primary factors limiting germination and seedling growth. Seed priming with plant growth regulators is one of the popular approaches to minimize adverse environmental stresses. This study was carried out to examine the role of seed priming with 5-aminolevulinic acid (5-ALA) at different levels (0, 25, 50, and 100 mg L-1) in germination and seedling growth of three wheat (Triticum aestivum L.) 'Emam', 'Gomria', and 'Zakia' under high temperature and drought stresses using a range of temperatures (25, 30, and 35 ºC) and water potentials (0.0 and -0.5 MPa). Water uptake, germination and early seedling growth attributes were measured. Drought stress and high temperature decreased germination%, germination index, and shoot fresh weight by 39.2%, 35.4%, and 48.6%, respectively, as compared with 0.0 MPa and 25 ºC. Seeds of 'Zakia' primed with 50 mg L-1 5-ALA at -0.5 MPa, and 35 ºC increased fresh and dry weights of the root by 19.8% and 68.4% relative to 0 mg L-1. For interaction between variety and 5-ALA, the highest germination% (90.3%) was recorded in 'Emam' with 50 mg L-1 5-ALA. Treatment 100 mg L-1 5-ALA decreased mean germination time by 24.5% and 28.9% at 25 and 35 ºC, respectively; 50 mg L-1 5-ALA increased seedling vigor index by 16.3% as compared with 0.0 mg L-1 at -0.5 MPa and 35 ºC. The 5-ALA enhanced water imbibition of the three varieties under drought and temperature stresses. This study suggested that seed priming with 5-ALA is a possible way to mitigate the negative effects produced by drought and temperature stresses on germination and early seedling growth of wheat.
Keywords: Abiotic stress, early growth stage, plant growth regulator, Triticum aestivum, water imbibition.
1Yangzhou University, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou 225009, China.
2University of Khartoum, Faculty of Agriculture, 11115 Khartoum, Sudan.
3Yangzhou University, Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou 225009, China.
*Corresponding author (gszhou@yzu.edu.cn).
4University of Al Qadarif, College of Agricultural and Environmental Sciences, 32214, Al Qadarif, Sudan.