Studies On Annual Growth Rhythm And Salt-tolerance Of Sinocalycanthus Chinensis Seedlings

The paper studied on annual growth rhythm and salt-tolerance of Sinocalycanthus chinensiswhich used one-year seedlings in pot as the object of study, respectively from the growth andmorphological, physiological and biochemical, photosynthetic characteristics angles, combiningwith the observation of ultrastructure.The annual growth rhythm mainly studied from March toNovember,and salt resistance test with six salt treatment of0%(CK),0.3%,0.6%,0.9%,1.2%,1.5%, the main results were as follows:(1) Sinocalycanthus chinensis in15days after sowing to emergence, from sowing to see-dling out lasted91days, and the germination rate was63.0%.(2) The one-year Sinocalycanthus chinensis seedlings’ annual growth rhythm was of obvio-us S type curve, and Logistic curve fitting effect significantly. The height growing dynamics ofseedlings could be divided into4stages: emergence phase(March15th-May14th), initiationphase(May15th-June1st)，prosperous phase(June2nd-July9th),later phase of seedling (June2nd-July9th); the ground diameter growing dynamics could be divided into3stages: emerge-nce phase(March15th-May13th), prosperous phase(May14th-October8th), later phase (Oc-tober9th-November25th).In the process of growth, the total root surface area, total root length,root volume, root average diameter, taproot length, root morphology index, and leaf length, leafwidth, leaf area, leaf morphological indexes were on the rise, but the pace was different; leavesfrom oblong to ovoid by development, but length were always larger than width; variousphysiological indicators were change in different, total chlorophyll presented the change trend of“low-high-low”, chl a/b and dissoluble protein content in general were “higher-reduce-higher-reduce” trends, dissoluble sugar content in the change trend of “rise-down-rise”; photosynthesiswere very different in different seasons, in spring and autumn, Pn,Gs,Tr diurnal variation was the“single-peak curve”, but summer had “noon break”phenomenon,“double peak”curve.(3) Sinocalycanthus chinensis seedlings with a certain ability of salt tolerance could grownormally in0.3%concentrations, and0.6%concentration of seedlings appeared to the emergen-ce of the phenomenon of death; total biomass, root, stem and leaf biomass of different organs g-rew rapidly at low concentration, but when the concentration was higher than0.6%, biomass gr-owth were inhibited in different degrees, and with the increase of concentration, the inhibitiondegree increased; with the increas of NaCl concentration, leaf tissue water content, chlorophyllcontent,dissoluble protein content gradually decreased, SOD ac-tivity, Pro content increasedgradually, Pn，Gs，Tr decreased,diurnal change presented obvious or not obvious double-peakcurve; Sinocalycanthus chinensis ultrastructure showed that the salt stress had a great influenceon the chloroplast traits,and thylakoids expansion, arranged disorder even ablation, andmitochondria and cell nucleus changed a little.