Organic compounds accumulation in Ceiba glaziovii (Kutze) Kum. seedlings in response to intermittent drought.

Abstract

Ceiba glaziovii (Kuntze) K. is an economically and ecologically important species occurring in Caatinga.. However, information about its physiological responses to drought during initial seedling phase are nonexistent. The present work aimed to evaluate the leaves relative water content, and the accumulation of osmotically active organic solutes in Ceiba glaziovii seedlings submitted to intermittent drought. Thus, one month old C. glaziovii seedlings were subjected to intermittent drought by irrigation suspension cycles [control with daily watering (C), irrigation every seven days (E7), watering suspension until signs of wilting as severe stress (ES) e re-watered (RE), checking recovery after 72h]. Height, stem diameter, relative water content (TRA), free proline concentration (PL), carbohydrates (CS) and protein (PS) in leaves and roots were evaluated.. The intermittent drought had little effect on TRA of C. glaziovii seedlings, but negatively affected growth. There was no accumulation of CS in the leaves, but a great variation in PL and PS content were observed. In the roots of E7 plants there was significant accumulation of CS, PL and PS, indicating the role of these compounds in the osmotic adjustment in the root system. Ceiba glaziovii maintains adequate tissue water values in intermittent drought conditions during its initial development phase. Proline accumulates in leaves and roots in response to moderate water deficit, suggesting an important role for species survival.