The Effect Of Temperature On Phyllostachys Violascens Shooting

Phyllostachys violascens is a good bamboo species for bamboo shoots production,and the winter dormancy of its shoots is similar to endo-dormancy of some plant buds.Release of endo-dormancy needs chilling,and buds cannot grow out by simply changing environmental conditions.In order to determine the type of winter dormancy of Phyllostachys violascens shoots and the temperature requirements for dormancy release,this paper used potted seedlings to establish a chilling-forcing experiment system.The potted seedlings under natural chilling treatment were transferred into the forcing condition at 2 weeks intervals to study the chilling requirement of bamboo shoot.4 forcing conditions with an average temperature of 26?,21?,16?,and 11?,respectively,were set to study how the forcing temperature and chilling affect bamboo shoot.Status of plasmodesmata was observed with transmission electron microscopy(TEM),and carbohydrate and enzyme activity of reactive oxygen species(ROS)were measured to explore the intrinsic effect of temperature on shoot dormancy release.Following are the results:Mean days for bamboo shooting(Mean DBB)decreased significantly with duration of chilling in 4 forcing conditions.Mean DBB in 4 forcing conditions(the set average temperature from high to low)were 14.0,32.3,78.0,129.4 days respectively when seedlings had no chilling accumulation.They were 6.8,10.6,10.8,12.7 days,respectively,with sufficient chilling.That means chilling can promote dormancy release of bamboo shoots,and widen growth temperature.High temperature can supplement the effect of chilling shortage to some extent.The type of winter dormancy of bamboo shoots is endodormancy.The plasmodesmata of the shoot apical meristem of dormant bamboo shoots were blocked,and the growth of the shoots was slow.With the increase of the duration of chilling,the blocked Pd was reopened and the shoots resumed rapid growth.The contents of soluble sugar and starch in shoots increased with the duration of chilling,indicating that carbohydrate metabolism is related to the process of dormancy release.At the same time,the activities of SOD,POD,CAT and APX related to ROS metabolism in bamboo shoots were also measured.It was found that SOD,POD and CAT had a downward trend as the duration of chilling,while APX was opposite.