Study On Optimization Technology Of Dendrocalamopsis Oldhamii Container Seedling Cultivation

Dendrocalamopsis oldhami?Munro?Keng f.is an important economically bamboo shoot species in the southern subtropical region of China.In recent years,extreme precipitation events,regional temperature rised in the spatial and temporal patterns of precipitation,due to global environmental and climate changes,have further led to an increase in the geographical differentiation of regional soil moisture changes,which to a certain extent,these dameges can be greatly avoid by using container seedling.Due to their multiple characteristics of different seedlings,the cultivation required a big difference.Another reason that the study of bamboo container seedlings in china is still in its infancy,and the foundation planting practices is still relatively lacking.the experiment,including orthogonal test to screen the matrix formula of Dendrocalamopsis oldhami container seedlings,artificial water control simulated physiological and biochemical changes of Dendrocalamopsis oldhami under drought stress environment,shading net coverage simulated physiology and growth changes of Dendrocalamopsis oldhami under shading environment and the three-factor quadratic orthogonal rotation design to study the growth of Dendrocalamopsis oldhami under different ratios of N,P and K were carried out in the nursery greenhouse of Fujian Yongan Forestry?Group?Incorporated Company during2017 to 2018,in order to provide a reasonable reference for cultivation and management during the seedling stage,offering a theoretical reference for Dendrocalamopsis oldhami afforestation,and cultivation for bamboo shoots,The following main conclusions are presented in this thesis:1.Screening of key influencing factors and light matrix formulas for Dendrocalamopsis oldhami container seedling cultivationThe orthogonal results of L₉?3⁴?for key growth factors of Dendrocalamopsis oldhami seedlings indicated that the primary factors affecting growth and shoot amount of Dendrocalamopsis oldhami were:fertilizer type>matrix type>container size>container type,and the optimal level combination D2C1B3A1?the application of organic fertilizer,peat and perlite?7:3?as the substrate,container size of 25 cm×23 cm×23 cm?upper base diameter×bottom diameter×pot height?,Container made of non-woven fabric?.Above the four factors,the type of fertilization and the type of matrix are dominant factors,the type of container has little influence.Further verification was carried out by adding the chaff to the optimal matrix?peat and perlite 7:3?to improve the soil porosity.The result showed that matrix ratio with peat:perlite:chaff at 7:2:1 get better seedling effect.2.Photosynthetic physiological response of Dendrocalamopsis oldhami container seedlings in the process of water lossUnder the condition of lack of water supplement,the results showed that P_n,LSP,LCP and R_dof Dendrocalamopsis oldhami were closely related to SRWC and PAR,and a significant threshold response also shown.The soil moisture in the range of 53.5%?SRWC?69.6%a“turning zone”was observed,in which various physiological parameters change along with SRWC.Dendrocalamopsis oldhami had good photosynthetic physiological adaptation in53.5%?SRWC?95.6%,and no obvious occurrence of light suppression.3.Physiological characteristics of Dendrocalamopsis oldhami container seedlings under drought stressArtificial watering was applied to the Dendrocalamopsis oldhami container seedlings to simulate drought stress for one month,and the 5 kinds of water control treatments were CK?more than 75%of the field water holding capacity?,MS?50%to 55%of field water holding capacity?,SS?30%to 35%of field water holding capacity?,MS-CK?rehydration after moderate drought stress?and SS-CK?rehydration after severe drought stress?.The results showed that under moderate drought stress?MS?,the impact of Dendrocalamopsis oldhami was affected small,and under severe drought stress?SS?,daily average water consumption,root activity and antioxidant enzymes all reflected the damage of the main vegetative organs of Dendrocalamopsis oldhami.After rewatering,the Dendrocalamopsis oldhami showed a certain compensatory effect on the stress resistance,which showed that the root activity was close to the normal level under moderate drought stress,the antioxidant enzyme activity was higher than the normal level,and has been subjected to better stress resistant exercise.After the membrane lipid permeability was slightly damaged,the accumulated malondialdehyde?MDA?content was also close to normal under moderate drought stress.In general,plants maintain high root activity,protective enzyme activity,and lower MDA content under drought stress and rehydration conditions,to a certain extent,having a better drought resistance and high yield characteristics.The daily variation of photosynthetic transpiration parameters between CK,MS and SS showed that the net photosynthetic rate and the transpiration rate were positively correlated with the drought stress.The reduction of soil water supply significantly reduced the net photosynthetic rate and transpiration of Dendrocalamopsis oldhami,and decreased the accumulation of photosynthetic products.The water use efficiency showed a bimodal curve and positively correlated with the degree of drought stress,but there was no significant impact on water use efficiency after drought stress increased.4.The growth,physiology and quality changes of Dendrocalamopsis oldhami container seedlings under different shading levelsThe shading shed was covered to simulate the growth regularity and physiology of Dendrocalamopsis oldhami container seedlings.The results showed that the photoresponsiveness,the daily photosynthetic change,the chlorophyll fluorescence parameters,the chlorophyll content,the antioxidant enzyme activity,the membrane lipid peroxidation and the growth indicators of Dendrocalamopsis oldhami seedlings had different influence after shading.Photosynthetic transpiration parameters such as P_n,WUE and PSII original light energy conversion efficiency?F_v/F_m?were suppressed in full light environment?L₀?and excessive shading environment?L₂?.The antioxidant enzyme system performed more sensitive response to the shading environment,and a better ability to scavenge active oxygen in different shading environments.Under the condition of lightly shaded L₁(70%of full light,925?mol·m^-2·s^-1),the Dendrocalamopsis oldhami container seedlings had better physiological adaptation,and stimulated the growth of base diameter,which helps cultivate strong seedlings.5.The growth and seedling quality of Dendrocalamopsis oldhami container seedlings under different N,P and K levelsThe three-factor quadratic orthogonal rotation design was used to study the growth and the seedling quality of Dendrocalamopsis oldhami under different ratios of N,P and K.The results showed that the Dendrocalamopsis oldhami seedlings had good utilization ability to N and P fertilizers,but fewer K fertilizers absorption.The single factor effect analysis showed that the K concentration in the test range had no significant effect on the growth of Dendrocalamopsis oldhami seedlings,and the N and P fertilizers had obvious interactions.That is,in the Dendrocalamopsis oldhami growing season?3-9 month?,the nutrient solution200 ml/pot is applied,and the monthly application is 2 times.The optimum fertilization levels of N,P and K are N 146.11 mg/L,P 53.62 mg/L.K 52.61 mg/L,with which reached the maximum yield?fresh weight?238.66 g/pot.