The Effect of Sowing Date on Plant Growth and Nutritional Value of Cichorium spinosum L. Plants

Cichorium spinosum L. is a wild edible green, native to the Mediterranean basin, which usually grows in coastal areas and plateaus. In the present study, plant growth and mineral composition of C. spinosum was evaluated for two consecutive growing periods. Seeds of C. spinosum were sown in seed trays on 15^th of October, 2013 and 17^th of January, 2014 and young seedlings were transplanted on 12^th of December, 2013 and 7^th of March, 2014 respectively. Harvest took place at marketable size. Seed germination rate was lower than 50% at both sowing dates (46 and 38%, for 1^st and 2^nd sowing, respectively), whereas seedling emergence was complete after 11 and 18 days, for the 1^st and 2^nd sowing date, respectively. Leaf fresh and dry weight, and rosette diameter did not differ significantly, whereas number of leaves and total leaf area was higher in the 1^st sowing. Regarding mineral composition, Ca, Mg and Mn content was higher in the 2^nd sowing date, whereas K and Na in the 1^st sowing date. Fe and Zn content was not affected by sowing date. Regarding nutritional value, ash content increased in the 2^nd sowing date, whereas protein and carbohydrate content decreased. However, fructose and glucose and consequently total sugars content, and ascorbic acid content increased in the 2^nd sowing, whereas α-tocopherol and total tocopherols, and chlorophyll b decreased. Fatty acids consisted mainly of linoleic, α-linolenic and palmitic acids, whereas no significant differences were observed between the two sowing dates. PUFA/SFA and n-6/n-3 ratio was higher than 0.45 and lower than 4.0, for both sowing dates. In conclusion, sowing date affected plant growth in terms of leaf number and leaf area, without affecting leaf fresh weight, whereas second sowing resulted in an increase in sucrose, glucose and total sugars content and ascorbic acid content that could improve the taste and nutritional value of the final product.