THE INFLUENCE OF LIGHT ON GROWTH PARAMETERS OF PEPPER (Capsicum annuum L.)

Kvaliteta i količina svjetla su važni faktori za proizvodnju kvalitetnih presadnica povrća. Djelotvoran dio spektra za fotosintezu je u području crvene i plave svjetlosti pa se u proizvodnji presadnica često koristi dopunska LED rasvjeta koja emitira svjetlost upravo pri rasponu navedenih valnih duljina. Cilj ovog istraživanja je bio utvrditi utjecaj crvenog, plavog te kombinacije crvenog i plavog LED i flurescentnog svjetla na morfološka svojstva, SPAD indeks te sadržaj klorofila, karotenoida i fenola u listu paprike (Capsicum annuum L.) u dva termina mjerenja tijekom rasta paprike. Najveći sadržaj klorofila, karotenoida, SPAD indeks te najveća lisna površina je utvrđena u varijanti tretmana crveno+plavo LED osvjetljenje. Najniže vrijednosti širine i dužine listova su utvrđene kod biljaka uzgajanih pod crvenim LED svjetlom dok je najmanja ukupna visina biljaka utvrđena kod biljaka uzgajanih pod fluorescentnim svjetlom. Iz navedenih rezultata možemo zaključiti da dodatno LED osvjetljenje koristeći kombinacije svijetlosti iz plavog i crvenog dijela spektra može pozitivno utjecati na rast i razvoj presadnica paprike. Daljnjim istraživanjima je potrebno utvrditi najpovoljniji omjer valnih duljina iz navedenog dijela spektra kroz pojedine faze rasta i razvoja ali i za pojedine sorte, pošto brojna istraživanja potvrđuju da je različiti odgovor pojedinih sorti unutar iste biljne vrste.The quality and quantity of light are important factors for the production of quality seedlings of vegetables. Effective portion of the spectrum for photosynthesis is in the red and blue light, however, in the production of seedlings additional LED lighting that emits light just in the range of those wavelengths are often used. The aim of this study was to determine the effect of red, blue and combinations of red and blue LED lights and flurescent lights on morphological characteristics, SPAD index and the content of chlorophyll, carotenoids and phenol in the leaves of pepper (Capsicum annuum L.) in two terms of measurements during the growth. The highest content of chlorophyll, carotenoids, SPAD index and the largest leaf area was established in the treatment red + blue LED illumination. The lowest values of the width and length of the leaves were found in plants grown under red LED light while the lowest total plant height determined in plants grown under fluorescent lights. From these results we conclude that additional LED lighting using a combination of light from the blue and red parts of the spectrum can positively affect the growth and development of seedlings of pepper. Further research is needed to determine the most favorable ratio of before mentioned wavelengths of the spectrum through the stages of growth and development as well as for individual varieties, because numerous studies confirm different response of certain varieties in the same plant species