Investigating the potential of using Nipeat substrate in the production of watermelon seedlings (Citrullus lanatus L.) with an emphasis on photosynthetic responses

In the present study, the effects of Cocopeat, Nipeat and Perlite on the morphological, physiological and photosynthetic performance of watermelon seedlings were studied based on randomized complete block design. Plant seeds after preparation were cultured in 6 culture media including 1) 100% cocopeat (CP100); 2) 100% Nipeat (NP100); 3) 50% Cocopit+50% Nipeat (CP50+NP50); 4) 25% cocopeat + 50% Nipeat + 25% Perlite (CP25NP50P50); 5) 50% Nipeat +50% Perlite (NP50+P50); 6) 70% Nipeat + 30% Perlite (NP70+P30). Germination indicators such as germination percentage and rate were calculated and after the seedlings reached the stage of transfer to the field, morphological, physiological and chlorophyll fluorescence characteristics were examined. The results indicated a high vegetative performance of the Watermelon seedlings in the CP100 treatment, but in the substrates containing perlite, a decrease in all the studied morphological traits and photosynthesis performance was observed. When CP100 culture medium was used, the highest amount of chlorophyll a, b and total, carotenoids and relative content of leaf water and the lowest amount of proline were reported. Therefore, according to the results obtained in the present research, it can be stated that the use of 100% cocopeat can lead to better growth of Watermelon seedlings.