Putrescine Affects Fruit Yield and Quality by Promoting Effective Pollination Period in Citrus limon

It is important to know the effects of extreme temperatures on reproductive biology within the scope of climate change. Polyamines play significant roles against stress conditions that are related to abiotic stress responses. For this reason, polyamines take an important role in terms of growing, development and stress tolerances by coping with the negative effects of several ecological conditions. In this research, Citrus limon cv. ‘Meyer’ was used. The aim of this study was to determine the effects of different doses and treatment periods of putrescine on pollen germination, in vivo pollen tube growth, ovule longevity, fruit yield and some fruit quality parameters. As a result of the study, it was determined that putrescine treatment increased in vitro pollen germination level, accelerated in vivo pollen tube growth for 2 days and prolonged ovule viability by at least 10 days. At the same time, especially 8 ppm putrescine treatment at the beginning of flower bud formation increased fruit set 70% by increasing fruit number on the tree without any dimensional reduction. Fruit juice acidity was increased as much as 2% with putrescine, which is an important fruit quality parameter for lemons. The germination of the obtained seeds was also increased via putrescine treatments from 52.0% to 71.3%. In conclusion, 8 ppm putrescine treatment at the beginning of flower bud formation resulted in faster pollen tube growth and longer ovule viability, which in turn provide a longer effective pollination period (EPP).