Allometry, Dry Matter Accumulation Models And Photosynthetic Behavior Responded To Nitrogen In Salvia Miltiorrhiza Bunge

Salvia miltiorrhiza Bunge is an important medicinal resource. Interpreting themorphological growth pattern, photosynthetic and dry matter accumulation process is of greatimportance. The content mainly contains four parts.1. The allometric growth pattern of S. miltiorrhizaReduced major axis （RMA） was applied to fit the relationship between height anddiameter, height and gross, respectively. Results showed that simple allometric relationship,that was, power exponent function, occurred between them. There was a strong positivecorrelation between them. Height tended to increase with the thickening of diameter. At thespecific height, the larger diameter and biomass, the more powerful ability against adversity,that’s beneficial for surviving.The biomass of root, stem and leaf all had an allemetric relationship with total biomass.And so did the aboveground and belowground. All of them behaved power exponent function,simple allometric relationship. Results exhibited that the biomass distribution of abovegroundwas higher than belowground, which was beneficial for matter accumulation. Moreover, thebiomass distribution in leaf was more than root and stem, and so did root than stem. Theconclusion could be drawn that the competitive relationship was not fierce under experimentaldensity condition (1.2×104plants ha^-1).2. Photosynthetic performance response to irradiance and CO2of S.miltiorrhizan with threenitrogen levels treatments under field conditionsThe classic Farquhar light-response model is fit for S. miltiorrhiza. Under experimentalconditions（CK, N100and N200）, the apparent quantum yield （AQY） are all above0.06molmol^-1, which is higher than others C₃plants with the AQY being about0.055mol mol^-1. Lightcompensation point （LCP） has a range of54-70μmol m^-2s^-1, and light saturation point （LSP）is1600^-1800μmol m^-2s^-1.The maximum net photosynthetic rate （Amax） are all above20μmolm^-2s^-1. Non-uniform stomatal closure led to the measured Cihigher than the actual one, so thefalse appearance happened in the non-uniform stomatal limitation. Nitrogen did notsignificantly change AQY, but enhanced LCP, LSP and Rd, while Amaxdecreased slightly. Compared to CK, LCP of N100and N200improved18.206%and27.286%, and LSPimproved11.012%and7.164%, respectively. Therefore, the range of light utilization hasexpanded from54^-1689μmol m^-2s^-1to69^-1810μmol m^-2s^-1. The dark respiration rate （Rd）improved, so a slight decrease in Amax.In addition, A-Cc CO2-response biochemical model of Sharkey is appropriate for S.miltiorrhiza. The three limitation parameters of maximum rate of carboxylation （Vcmax）,maximum rate of electron transport （J） and triose phosphates utilization （TPU）, which areclosely related to the carbon assimilation process. Under the experimental conditions, Vcmaxis150^-164μmol （CO2） m2s1, J is139^-145μmol （e）–m2s1and TPU is9^-10μmol （CO2） m2s1.Nitrogen significantly improved Vcmaxand J except TPU. Compared to CK, Vcmaxof N100and N200improved7.299%and9.314%, respectively; and J of N200improved3.571%,while J of N100did not change dramatically.3. Simulation of leaf area index and dry matter accumulation in Salvia miltiorrhiza Bge.For the whole growth analog system and long-range control in S. miltiorrhiza, models forLeaf Area Index （LAI） and photosynthesis-driven dry matter were developed. Thermaleffectiveness and photosynthetically active radiation （TEP） was quoted to develop themechanistic LAI model. According to the canopy structure of Salvia, a3-layer model wasestablished in combination of LAI model and Gaussian integration. Considering the effect oftemperature on maximum photosynthesis rate, perpendicular hyperbola model was chosen toquantify photosynthesis. The model calculated maintenance respiration and growth respirationwhich consumed part of the photosynthate. The shoot would lose some dry matter due toinward and outward factors during the late growing period, including declined temperatureand decreased irradiance. Partition index of shoot was quantified by TEP to calculate shootdry matter from plant biomass. The senescence and dried-up of shoot was deducted tosimulate the dynamic biomass accumulation process precisely. Model accuracy was validatedto the independent experiment2by three different statistical indices: Root mean squared error（RMSE）、Relative error （RE） and the index of agreement （d）. There was a significantagreement between predicted and observed values. All their coefficients of determinationwere higher than0.992. RE was about10%, and d approached to1. Results show that thismodel appears to be favorable and reliable and can offer theoretic basis for forecastingproduction, optimizing management and long-range control for Salvia in the future.