Stomatic behaviour and leaf water potential in young plants ofAnnona squamosasubmitted to saline stress

Abstract

Stomatic behaviour and leaf water potential in young plants of Annona squamosa submitted to saline stress. Abstract-Introduction. In saline soils, the water absorption process of the plants is negatively affected, due to the permeability of the roots, leading to hydric stress. Plants under saline stress close their stomas earlier than plants not in these conditions; this causes an increase in stomatal resistance due to the decrease in water potential. The aim of the present research was to detect alterations in the stomatic behaviour and leaf water potential in young plants of Annona squamosa submitted to saline stress. Materials and methods. Sixty-day-old seedlings of A. squamosa were acclimated for 15 days in a greenhouse, before being submitted to different saline treatments. Five treatments (T 0 = 0 mM; T 1 = 25 mM; T 2 = 50 mM; T 3 = 75 mM and T 4 = 100 mM of NaCl in a nutritive solution) were applied with six replications. The evaluations of the stomatic response occurred on the 20th, 30th, 40th, 60th, 80th and 90th days after the beginning of the saline treatments. The transpiration measures, diffusive resistance and leaf temperature were registered in the first mature leaf. The photosynthetically active radiation, relative humidity and air temperature within the greenhouse were simultaneously assessed 60 and 90 days after the beginning of treatments; then the leaf water potential (R leaf) was also measured. Results. During the time of the experiment the leaf temperature and its difference from the air temperature was not affected by NaCl levels, but only 90 days after the beginning of the treatments the values observed in the control plants were lower than those observed in the 25 mM treatment. The diffusive resistance after 40 days was increased in all NaCl treatments. The transpiration, independent of treatment, was reduced by 44.1% (at 60 days) and 13.4% (at 90 days) with the 100-mM treatment compared with the control treatment. The increment in NaCl induced a decrease in R leaf in all treatments, but an equal reduction was observed for each treatment after 60 and 90 days. Conclusion. The NaCl levels affected the transpiration and leaf water potential; however, the leaf water potential showed an equal reduction in all treatments on the 60th and 90th days. Brazil / Annona squamosa / soil salinity / osmotic stress / transpiration / stomata / water potential Résistance stomatique et potentiel hydrique foliaire chez de jeunes plants d'Annona squamosa soumis à des stress salins.

Proteomic Analysis of Maize Cultivars Tolerant to Drought Stress

“…Furthermore, it is important to note that when subjected to stressed conditions, plants need to acclimate to the unfavorable environment factors, such as climate, soil, and temperature. [21]. In this context, acclimatization refers to inherent changes in gene expression and the production of specific compounds during exposure to stress conditions.…”