Abstract
Plant species have developed a great number of mechanisms to maintain their reproduction and defend themselves during stressful conditions. Both primary and secondary metabolisms are affected by environmental changes at different stages of plant development. Thus, it is important to know plant defense and resistance mechanisms to environmental variations adapted to different environmental conditions. Parkia platycephala is an endemic species to Brazil and has several potential uses for pharmacological, forage, wood, ornamental and ecological purposes. Herein, we analyzed the relationship between climatic seasonality, phenology and physiology of Parkia platycephala. The study was carried out in a Cerrado sensu stricto area located in the region of Serra da Bandeira (12º05’S and 45º02’W), Barreiras, Bahia, Brazil. The phenological phases of Parkia platycephala were observed monthly following the methodology of Fournier. Leaves from the same individuals selected for phenological evaluations were sampled for physiological analyzes and the photosynthetic pigments, total phenol content, antioxidant activity, total soluble sugars (TSS), reducing sugars (RS) and non-reducing sugar (NRS) were quantified. Parkia platycephala presented a seasonal semi-deciduous vegetative pattern and annual reproductive pattern. The low water availability was the main environmental driver which most affected the physiological processes, reducing chlorophyll a and carotenoid production and promoting an increase in chlorophyll b, total phenol and non-structural soluble carbohydrate production. The non-enzymatic antioxidant activity in Parkia platycephala was high, presenting 3.7-times higher values than ascorbic acid (Vitamin C). Thus, this species presents effective mechanisms to maintain its active physiological processes, supporting droughts and intense sunshine throughout the year; however, its carbohydrate production is negatively affected by environmental shifts, thereby reflecting their phenophases, specifically on the reproductive phenophase.
Keywords:
Faveira; Abiotic stress; Plant metabolism
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Fonte: Instituto Nacional de Meteorologia (INMET) (2018)
Fonte: Autoras (2018)
Fonte: Autoras (2018). Em que: Chla - clorofila a; Chlb - clorofila b; Chl total - clorofila total; mf - massa fresca. As médias foram comparadas pelo Teste de Tukey ao nível de 5% de probabilidade. Médias seguidas da mesma letra, nas séries, não diferem significativamente pelo teste de Tukey (p≤0,05).
Fonte: Autoras (2018). Em que: AST - Açúcar Solúvel Total; AR - Açúcar Redutor; ANR - Açúcar Não-Redutor. As médias foram comparadas pelo Teste de Tukey ao nível de 5% de probabilidade. Médias seguidas da mesma letra, nas séries, não diferem significativamente pelo teste de Tukey (p≤0,05).
Fonte: Autoras (2018). Em que: As médias foram comparadas pelo Teste de Tukey ao nível de 5% de probabilidade. Médias seguidas da mesma letra, nas séries, não diferem significativamente pelo teste de Tukey.
Fonte: Autoras (2018). Em que: As médias foram comparadas pelo Teste de Tukey ao nível de 5% de probabilidade. Médias seguidas da mesma letra, nas séries, não diferem significativamente pelo teste de Tukey.