Physiological Response of Tomato Seedlings to Air Humidity under High Temperature

In order to study the physiological effects of air humidity on the heat stress of tomato seedlings,3levels of air humidity treatment including non-humidification(L treatment,CK),55 %±5%(M treatment)and 70%±5%(H treatment)were carried out in this article with artificial growth chambers.The results showed that under the high temperature with the average temperature 33 ℃from 10:00to 16:00,osmotic adjustment substances and peroxidase activity increased with treated time.Membrane permeability of tomato seedlings decreased with treated time in H treatment;however plasma membrane permeability of tomato seedlings increased with time in L and M treatments.During the whole test period,compared with L treatment,tomato seedlings in H treatment had 25%-70%less for proline content,and 14%-32%lower for peroxidase(POD)activity,which indicated that tomato plants in RH70%±5%suffered slight heat stress.In conclusion,RH70%±5%(H treatment)decreased heat injury indices and improved heat resistance of tomato seedlings.