The Effect Of Patchy Fertilization On The Specialization Of Rhizome System For Phyllostachys Pubescens Forest

As one kind of the important economic bamboo species in the south of China, phyllostachys pubescens has monopodium type rhizome, its overground parts belong to scattered distribution type.Through the growth process of a bamboo shoot to a young bamboo, it develops such a clonal population in which muti-generation ramets coexists. Actually, it is produced by vegetative propagation of underground rhizome of countless genets. The research of morphology and physiological and ecological characteristics of clone population has guiding significance to the understanding of growth and reproduction of phyllostachys pubescens rhizome. This article studied specialized phenomenon of rhizome system for phyllostachys pubescens forest with the method of patchy fertilization. The results showed that:1.The seasonal dynamic changes of fine root(0- 1 mm、1-2 mm、0-2 mm and 2-5 mm) biomass showed that April and October possessed the maximum biomass. The fine root with fertilization treatment changed a lot and the ones without fertilization treatment had little change. The annual average biomass of fine root with different diameters under different fertilization treatments all reached significant level(p<0.05),with the increasing of fertilizer application rate, the biomass of fine root had the tendency to increase and showed that F3>F2>F1>CK. While the biomass of dead root didn’t reach significant level(p>0.05). It demonstrated that the biomass of fine root had specialized phenomenon of fertiliertaxis in time and space.2. Root vigor and the activity of Nitrate reductase(NR) and Glutamine synthetase(GS) reached significant level(p<0.05)among different fertilization treatments in six sampling time, it showed that TR3>TR2>TR1>CK, the activity of Acid phosphatase showed that CK>TR1>TR2>TR3.The correlation analysis indicated that the root vigor and the activity of Nitrate reductase, Glutamine synthetase and Acid phosphatase had significantly or high significantly positive correlation(p<0.05);the activity of Acid phosphatase negatively correlated with the content of soluble protein(p<0.01). It proved that fertilization treatment could enhance the ability of root system to acquire the nutrients and improve the active adopting ability of the transmission of nutrients, root system had physiological plasticity to some extent.3. The annual average biomass of fine root with different diameters(0- 1 mm、1-2 mm、0- 2 mm、2-5 mm) using deficient treatment under different nutrient conditions all reached significant level(p<0.05), it showed that NPK>NP>PK>NK>CK. Fine root with different diameters(0- 1 mm、1-2 mm、0- 2 mm、2- 5 mm) all reached significant level(p<0.05)in February, June and October. While only in April and December the biomass of fine root(1- 2 mm) reached significant level(p<0.05), the biomass of dead fine root reached significant level( p<0.05) in December merely. It indicated that morphological plasticity of root system changed to a variable extent and deficient treatment inhibited the growth of fine root significantly, especially for P, N and K.