Physiological And Ecological Characteristics Of Phyllostachys Edulis In The Fast Growing Period

Phyllostachys edulis differs from other tree species in that it emerges as an "explosive" growth stage after excavated from young bamboo shoots.In order to elucidate the physiological and ecological strategies of Phyllostachys edulisin this special growth phase and to find out the causes of the "explosive" growth of Phyllostachys edulis,the ability of photosynthetic immobilization of organic compounds,the transport direction and intensity of nutrients,and the biomass distribution patterns and distribution of nutrients of different ages of Phyllostachys edulis were determined in the fast growing period.And compared with the corresponding value of the same period of off-year.The result indicated:(1)Phyllostachys edulis shoots high growth follows the "S" type,with its peak at around 18 d,at about 0.78 m/d.According to its high growth rate,it is divided into the early stage,the rise stage,the peak stage and the end stage.The daily growth of Phyllostachys edulis shoots has a significant correlation with air temperature,soil temperature and soil water content.(2)In the fast growing period,the relative chlorophyll content of all Phyllostachys edulis leaves showed: III degree bamboo> II degree bamboo> I degree bamboo.Except for the early stage,the relative chlorophyll content of bamboo in the fast growing stage was higher than that in the off-year period in the rising,the peak and the end stage,and the difference was very significant;In fast growing stage,the Pn of bamboo leaves showed: III degree bamboo> II degree bamboo> I degree bamboo.The Pn of each bamboo canopy at the early stage was higher than that of the corresponding stage in the off-year period,but the difference was not significant.At the rising stage,the difference between I and II was not significant,but the difference between II and III was significant,and the differences between I,II,and III degrees reached extremely significant levels in the peak and end stages;Yield,Fo,Fm and Fv / Fm all showed III degree> II degree> I degree during fast growing period,but NPQ and Fv / Fo values were the opposite.The values of Fo,Fm,Fv / Fo and Yield in fast growing period were all larger than the corresponding values in off-yaer period,while the Fv / Fm values were almost equal in both periods,but the NPQ value infast growing period was far less than that in corresponding off-year period.(3)In the fast growing period,the water potential of of all Phyllostachys edulis leaves is presented: III degree bamboo> II degree bamboo> I degree bamboo.The water potential of bamboo leaves in fast growing stage was higher than the corresponding value in off-year period,and the difference was significant.(4)In the fast growing period,the water content of organs in all bamboo showed leaves> stems> branches,and the water content varied with the bamboo age,and the biomass pattern of bamboo in all degrees fluctuated more slowly with no obvious regularity.The proportion of bamboo leaves biomass in fast growing period was larger than that in off-year period,and the difference reached a significant level,but there was no significant difference in biomass between stems and branches.(5)In the fast growing period,the content of nutrient elements in bamboo organs showed the highest content of nitrogen,followed by potassium and lowest of phosphorus.In fast growing period,nitrogen content in leaves,branches,stems and roots was lower than in off-year period,Phosphorus content in leaves and roots was lower than that in off-year period,but the content of phosphorus in the branches and stems was higher than that in off-year period,and there was significant difference in the leaves,branches and stems,The content of potassium in leaves,stems and roots was higher than that in the small ones,but the content of potassium in the branches was lower than that in off-year period,and the difference was significant in the leaves,branches and roots.In short,all the mother bamboo exhibited its own ecological and physiological strategies in fast growing period.Through the continuous supply of nutrients and energy,making young bamboo shoots show characteristics different from other species that is "explosive" growth.