Effects Of Drought Stress On Growth And Physiological Biochemical Characteristics Of Lily

Lily is an important economic flower crop.It not only can be used as an important cut flower,but also has important food and medicinal value.It has an important economic status at home and abroad.However,the occurrence of natural disasters such as drought severely restricted the development of the lily industry.When faced with drought stress,lily plants will resist and adapt to the bad environment through a series of physiological and biochemic a l defense mechanisms.In order to explore the mechanism of drought stress on the growth,physiological and biochemical characteristics of Lilium,we used lily as the experimental material in this study.Four different water gradients were set using potted water control method to determine the growth index,physiological and biochemical indexes of Lilium.The results of the study are as follows:(1)With the deepening of the drought stress,the speed of the lily plants high growth decreased significantly,and the development of roots and the formation of flower buds were also affected seriously.The more serious the degree of drought,the more significant the impact on the growth and development of lily.(2)With the increase of drought days,the chlorophyll content of lily significa nt l y decreased,and the EC increased.There was a negative correlation between the root activity of lily and the degree of drought,indicating that the greater of the degree of stress,the greater of the damage degree to the plant root system.After rehydration treatment,the chlorophyll content of lily increased significantly,even under the condition of LD,it exceeded the level of the Ctr,but did not return to normal level under HD.(3)With the increase of the drought degree,the antioxidant enzymes such as SOD,POD and CAT were not significantly different in LD and Ctr.MD and HD showed the trend of “rise first and then fall”.It showed that in the early stage of moderate and severe drought,lily plants could relieve the damage caused by drought through producing a large number of antioxid a nt enzymes.However,in the later period of the experiment,the long-term drought caused the destruction of the antioxidant system of the plant,and the enzyme content dropped drastically.With the increase of drought stress days and the deepening of the stress degree,MDA content increased,indicating that the greater the lipid membrane peroxidation,the greater the damage to the plant body.During the whole process of drought stress,the content of SS increased continuously,and the contents of SP and Pro increased first and then decreased,indicating that the response of different infiltration substances to drought stress was different.The response mechanism would have yet to be further explored.When the rehydration treatment started,the contents of SOD,POD,MDA,SP,and Pro in LD and MD decreased significantly.When rehydration was performed for 12 days,all biochemical indicators returned to the control group except for the HD group.Presumably,slight water shortage would not only not affect the growth of lily,but may also increase the drought tolerance of lily;long-term serious water shortage,due to excessive damage to the lily,even if the late rehydration can not make the lily recover To normal levels.