Growth and production of secondary compounds in monkey-pepper (Piper aduncum L.) leaves cultivated under altered ambient light

Abstract

The species Piper aduncum L., native to the Americas, has important biological benefits for the production of secondary compounds such as phenolics and flavonoids. Among the factors that influence the metabolism of the plant, is considered as one of the most important for promoting changes in plant physiology that can directly interfere in growth and production of secondary compounds. This study aimed to evaluate the growth and production of different secondary compounds (total phenolic acids, flavonoids, lignin and activity of phenylalanine ammonia lyase - PAL) of Piper aduncum L. The treatments were: four shading greenhouses (modified ambient lights), with 50%, 70% of natural irradiance, red and blue nets, and one at full sun (100% of natural irradiance), with 20 replicates per treatment. The growth of Piper aduncum was affected by the different altered ambient light, showing a higher growth under blue net. However, the species shows responses which allow its survival at full sun, such as more production of roots. The production of secondary compound was also affected by light, and the production of phenolic compounds and lignin higher (respectively 0.18 and 11.7 µg g DM-1 ) in treatment of blue net shade greenhouse. Moreover, PAL can be considered the key enzyme for the production of phenolic compounds in this species. The concentration of flavonoids in treatment with 100% irradiance was the lowest. This shows that the species has other mechanism of protection for high irradiance.