Salicylic acid (SA) is an important plant regulator reported as a mitigator of water deficit in plants, however without a recommendation for use in field conditions. Thus, this research aims to validate the use of SA under field conditions in regions with low water availability. For that, we evaluated CO₂ assimilation (A), stomatal conductance (g_s), transpiration (E), water use efficiency (WUE), and carboxylation efficiency (A/Ci) at 15, 30, and 45 days of continuous stress water deficit, as well as the application of salicylic acid (0.0; 0.5; 1.0; 1.5; 2.0 mM) in tomato plants subjected to continuous water deficit (45 days), in two years (2019 and 2020). The water deficit reduced the A, g_s, E and A/Ci, while the foliar application of SA increased these parameters in all evaluated times, resulting in similar or even higher values than in plants without water deficit. Water deficit caused floral abortion in tomato plants, without the application of SA, reducing the number of fruit production. In contrast, plants that received about 1.3 mM of SA increased A and A/Ci and translocated the photo-assimilates, mainly to flowers and fruits, reducing floral abortion and increasing fruit production. Thus, foliar application of SA was efficient in mitigating the deleterious effects of water deficit in tomato plants regarding the gas exchange and fruit production.

The maturation process of Sesbania virgata seeds was investigated through fruits and seeds at different maturation stages, where they were described morphologically. For the seeds, fresh and dry mass and moisture were determined and structural analysis of the tegument under a light microscope was performed. Germination tests in the presence and absence of drying and the electrophoretic profile of heat resistant proteins were also performed. The results showed that the seeds reached physiological maturity at 44 days after anthesis (DAA), evidencing a secondary cell wall. The acquisition of desiccation tolerance was observed at 44 DAA, with the seeds responding to the drying treatment. Protein bands were observed from 32 DAA, which remained constant until the end of maturation. These results allowed the characterization of the development and acquisition of desiccation tolerance in S. virgata seeds.

O objetivo do trabalho foi estudar os efeitos de diferentes concentrações do regulador vegetal proexadiona cálcica (ProCa) no controle do crescimento de mudas de tomateiro. O experimento foi conduzido no viveiro de mudas florestais da Faculdade de Ciências Agronômicas – UNESP, Campus de Botucatu–SP. O delineamento experimental foi o inteiramente casualizado, composto por cinco tratamentos: 0, 50, 100, 200 e 400 mg de ingrediente ativo (i.a.) de ProCa, com quatro repetições de 30 mudas cada. Os tratamentos foram aplicados com pulverizador manual de CO2 quando as mudas completaram 20 dias após a semeadura. Dez dias após a aplicação dos tratamentos foram realizadas análises de crescimento das mudas, índice SPAD, trocas gasosas, fluorescência da clorofila a e análises bioquímicas. Pelos resultados obtidos foi possível concluir que as concentrações de ProCa inibiram o crescimento das mudas, não comprometendo o funcionamento de seu aparato fotossintético.