Physiological Response of Seeds of Crotalaria spectabilis under Drought and Heat Stress

HIGHLIGHTS

• Water stress compromises seed germination.

• C. spectabilis tolerates up to an osmotic potential of -0.2 MPa.

• The temperature range between 25 and 30 ºC favors germination.

Abstract

This study evaluate the effect of drought and heat stress on the quality of C. spectabilis seeds. A completely randomized design in a 4×4 factorial scheme, referring to four osmotic potentials based on Polyethylene glycol (PEG 6000 = 0.0, -0.2, -0.4 and -0.8 MPa) and four temperatures (25, 30 and 35 ºC constant and alternating between 25-35 ºC), with four replications of 50 seeds per plot was used. The germination percentage, first count germination, germination speed index, average germination time, average germination speed, length and dry mass of the root, shoot and seedlings were evaluated. C. spectabilis is sensitive to drought stress during germination and seedling establishment, tolerating up to -0.2 MPa. The physiological quality of seeds is reduced with the decrease of osmotic potentials. The temperature range between 25 and 30 ºC are the one that provide better conditions for the germination of the seeds of this species.

Keywords:
Legume; seed physiology; germination temperature; vigor.