Effects Of Fertilizations On Leaf Characteristics And Photosynthesis Character During The Shoot Period To Deciduous Period Of Phyllostachys Pubescens

As we know,Phyllostachys pubescens that has the widest distribution and largest covering area in China is one kind of bamboos,which has the good ecologic,economic and social benefits.we based on its growth rhythm.bamboo forest in different fertilizer application modes were researched,the photosynthetic pigment, photosynthate, Photosynthetic rate and leaf nutrient elements were dynamic monitored during the shoot Period to Deciduous Period of the 4-year-old Phyllostachys pubescens and Photosynthesis character in the growing Period of Phyllostachys pubescens was also studied, providing theoretical basis and technical support to raise the level of scientific management of Ph. pubescens forest.The main results are as follows:1. Fertilization had no significant influence on Water content of the bamboo leaf;Fertilization significantly increased the bamboo thousand-leaf weight; Fertilization significantly increased leaf area index(LAI) of bamboo forest, LAI is highest untill August, LAI of bamboo forest fertilizatied in May is 11.19, higher than fertilization in August by 20.8%, higher than Non-fertilization by 43.5%; The increase of LAI was due to the increase the number of the new bamboos. A mean value of SPAD of the bamboo fertilizatied in May during its growing cycle (between March and Dec) is 41.1, higher than fertilization in August by 4.4% , than Non-fertilization by 18.0%.2. The content of chlorophyll a,chlorophyll b,carotenoids and photosynthetic rate were improved significantly by Fertilization, the order was Fertilization in May > Fertilization in August > Non-fertilization.But fertilization reduced the ratio of chlorophyll a and chlorophyll b, soluble sugar, reducing sugar and starch contents. Leaf(between March and Dec) photosynthetic pigment content and photosynthetic rate of fertilization in May maintain the highest level, so Fertilization in May is more conducive to increase the formation of photosynthetic products.3. Photosynthesis character of the 4-year Phyllostachys pubescens(in May) in three different fertilizer application modes was studyed.The results showed that: the diurnal variation of photosynthetic rate (Pn)and Transpiration rate (Tr)of Phyllostachys pubescens show the single-peak curves, and peaks occur at 13:00.The daily mean Pn and water use efficiency(WUE) of fertilization in May is higher than fertilization in August and Non-fertilization; The Light saturation point(LSP) Maximum photosynthetic rate(Pmax),Apparent quantum yield(AQY),CE of Phyllostachys pubescens fertilized in May are 1512μmol·m^-2·s^-1,9.45μmol·m^-2·s^-1,0.0226 mmol·mol^-1,1725μmol·mol^-1,0.0265,the order is Fertilization in May > Fertilization in August > Non-fertilization. The Light compensation point(LCP),CO2 compensation point (CCP) of Phyllostachys pubescens fertilized in May is lowest.In a word, Fertilization in May is more conducive to the improvement of the ability of photosynthesis of Ph. pubescens than that in August (the traditional fertilization).4.The average nutrient content(between March and Dec) of two-year leaf of Ph. pubescens are: N:20.96g·kg^-1;P:0.655g·kg^-1;K:7.53g·kg^-1;S:1.52g·kg^-1;Mg:0.809g·kg^-1;Ca:2.23 g·kg^-1;Fe:0.091 g·kg^-1;Zn:0.014 g·kg^-1;Cu:0.010g·kg^-1;Mn:0.391g·kg^-1;B:0.004g·kg^-1.Fertilization increased the leaf nutrient concentration of two-year leaf(except K,Mg,Zn).Fertilization increased the leaf nutrients accumulation, the order was Fertilization in May > Fertilization in August > Non-fertilization.