Research On Effects Of Crop Stubble And Altitude On Biomass Allocation And Photosynthetic Characteristics Of Fritillaria Przewalskii Maxim.

Fritillaria przewalskii Maxim,a member of the Lilly family native in China,is used in Chinese herbal medicine.Here we studied the dynamic characteristics of biomass allocation and photosynthetic characteristics of plant organs at different stages of vegetative and reproductive growth.The biomass allocation and photosynthetic characteristics of F.przewalskii at different cultivation conditions were studied by using an altitude gradient and differences in crop stubble.The morphological response strategies of leaf and bulb morphological characteristics along an altitude gradient were studied,and the allometric growth equation of various organs were established.This study revealed the response strategies in terms of growth characteristics and biomass allocation in F.przewalskii to the environment,these experimental results will play a positive role in the artificial cultivation of F.przewalskii The main conclusions are as follows:(1)The greatest net photosynthetic rate and light saturation point appeared at the vigorous growth period during vegetative growth stage.The mainly purpose is to consume the nutrients storaged in old bulb for the growth of root and leaf at the early growth stage,and produce organic material by leaf photosynthesis to storage in new bulbs.The biomass allocation pattern were bulb > leaf > root at each phenological period.(2)The apparent quantum yield of photosynthesis and the greatest net photosynthetic rate at budding stage and flowering stage are significantly higher than the fruit enlargement stage during reproductive stage,and the light compensation point and dark respiration rate reached the maximum at fruit enlargement period.The stem biomass allocation is the largest at budding period,and bulb biomass allocation is the largest at flowering stage,fruit enlargement stage and fruit ripening stage.The mainly purpose is to storage photosynthetic product in new bulbs and the mainly for vegetative growth at the early stage of the reproductive growth,bulb biomass allocation reduced and reproductive organ biomass allocation increased after flowering stage,the mainly purpose is used for sexual reproduction by consuming the bulb nutrients and guarantee the reproduction.The bulb biomass allocation increased after fruit enlargement stage,the mainly purpose is to storage photosynthetic product in new bulbs also.(3)During this experiment,various organs of F.przewalskii displayed isovelocity relationship from vegetative to reproductive growth,the allometric trajectory of bulbs:total plants,leaves: total plants and aboveground: underground parts are changed,and these differences of biomass allocation between the various organs related to the different life cycle stages and are real plasticity changes.The allometric trajectory of leaves vs.bulbs is not changed,the biomass allocation significantly correlated with plant growth stage,and is appearance plasticity changes.(4)Research on reproductive allocation character of F.przewalskii at different phonological stages,the results show that the biomass of reproductive organ had significant linear positive correlation with stem biomass,and had significant parabola relationship with the root and leaf biomass,and had significant linear positive correlation in flowering and had significant parabola relationship in fruiting with the biomass of bulbs and total.There were difference in growth rhythm of different organs,that was mainly related to the allocation of biomass in different organs.The highest content of nitrogen in leaf,reached 2.52%,phosphorus and potassium composition in the fruit were significantly higher than other organs in each phenophase.(5)Only leaf thickness has significant differences alone the altitude gradient,and the biomass allocation pattern are changed,with the increase of altitude,the leaf biomass allocation increased significantly,from 12.54% at 2400 m altitude increased to22.97% at 3000 m altitude,and bulbs biomass allocation decreased significantly,from87.46% at 2400 m altitude reduced to 77.03% at 3000 m altitude.With altitude increased,leaf photosynthesis parameters increased also,the plant of apparent quantum yield of photosynthesis,the greatest net photosynthetic rate,light compensation point,dark respiration rate and light saturation point in an altitude of2700 m and 3000 m are significantly higher than in an altitude of 2400 m in plants.It showed that F.przewalskii can increase its leaf thickness and photosynthesis rate to enhance its ability to protect itself and prolong leaf life.By increasing leaf biomass allocation to reduce bulb biomass allocation it can adapt to an alpine low temperature environment.The allometric analysis show that when bulb horizontal: vertica and total biomass is a fixed value,the plant has the largest bulbs biomass at an altitude of2700 m,2700 m might be ideal for developing its artificial cultivation.(6)Each organ biomass and total biomass in potato stubble are significantly greater than the wasteland and broad-bean stubble,and the greatest net photosynthetic rate and light saturation point in the potato stubble.The root absorption capacity and leaf photosynthetic efficiency of F.przewalskii growing in wasteland and broad-bean stubble increased,as did the biomass allocation to roots and leaves,resulting in reduced biomass allocation to the bulbs.Allometry analysis showed that growth strategy of bulb: leaf depends on the plant size difference,it is appearance plasticity changes,however root: total biomass,bulb: total biomass,root: bulb and aboveground:underground depends on the differences of crop stubble,are real plasticity changes.For artificial cultivation of F.przewalskii,potato stubble at an altitude of about 2700 m should be selected as the best cultivation site.The results of this study are helpful for the rational selection of plots and the effective increase in bulb output of F.przewalskii.