Studies On The Tissue Culture And Growth And Physiological Characteristics Of Chrysanthemum Cutting Seedlings Under Cadium Strees

Chrysanthemum is an important economic flowers, It’s important to study on the tissue culture and It’s resistance to heavy metal cadmium。In this text, take 11 potted chrysanthemum cultivars as the test materials, The rapid-micropropagation technology was discussed;The growth and physiological characteristics and cadmium enrichment condition of cutting seedlings under cadmium treatment were also studied. The results are indicated as follows:(1) Take stems with buds of 11 chrysanthemum cultivars as explants, the ‘Breeze Ivory’ had the highest induction rate, then took ‘Breeze Ivory’ as the further test material, and studied on the suitable proliferation medium, rooting medium, domestication and transplanting condition. the induction rate was 91.7%; The optimal proliferation medium of ‘Breeze Ivory’ was MS+6-BA1.0 mg/L+NAA0.1 mg/L+sucrose 30 g/L +agar 7.0 g/L, the multiplication coefficient was 12.1; The most suitable rooting medium of ‘Breeze Ivory’ was 1/2 MS+NAA 0.1 mg/L +sucrose 30 g/L +agar 7.0 g/L, and the rooting rate was 100%, the average number of roots per plant was 12.6;(4) The most suitable transplanting medium of ‘Breeze Ivory’ was river sand, and the survival rate was 98%.(2)The influence of different cadmium treatment concentrations on the growth indexes of chrysanthemum "Splash Sweet", "Rainbow Rosy" and "Breeze Yellow". With the increase of Cd concentration and treatment time, the plant height and root length of chrysanthemum cultivars decreased gradually. From low to high, the order of plant height decreasing level was ‘Breeze Yellow’, ‘Rainbow Rosy’ and ‘Splash Sweet’, while the order of root length decreasing level was ‘Splash Sweet’, ‘Rainbow Rosy’ and ‘Breeze Yellow’. After 30 days Cd treatment, with the increase of concentration, shoot dry weight and root dry weight declined gradually, The order of shoot dry weight declining level was ‘Breeze Yellow’, ‘Rainbow Rosy’ and ‘Splash Sweet’, while the order of root dry weight declining level was ‘Splash Sweet’, ‘Rainbow Rosy’ and ‘Breeze Yellow’. After 30 days Cd treatment, with the increase of Cd concentration, the toxic symptom became serious, shown as plant height decreasing, root length decreasing and new root number decreasing and leaves yellowing. ‘Breeze Yellow’ didn’t get yellowing under the 0.5mg/L Cd, which showed the least toxic symptom, followed by ‘Splash Sweet’ and ‘Rainbow Rosy’.(3) The influence of different cadmium treatment concentrations on the physiological indexes of 3 chrysanthemum cultivars. After 10 days Cd treatment, the content of chlorophyll a, chlorophyll b, total chlorophyll and carotenoid began to decrease compared with the control group. The decreasing trend became more and more obvious with the increase of the Cd concentration and treatment time. From low to high, the order of decreasing level was ‘Breeze Yellow’, ‘Splash Sweet’ and ‘Rainbow Rosy’. After 20 days Cd treatment, the photochemical efficiency began to decrease, From low to high, the order of decreasing level was ‘Breeze Yellow’, ‘Splash Sweet’ and ‘Rainbow Rosy’; After 30 days Cd treatment, the relative conductivity began to increase compared with control group, ’Splash Sweet’ and ’Rainbow Rosy’ increased gradually with the increase of the Cd treatment concentration, but ’Breeze Yellow’ decreased firstly and then increased,from low to high, the order of increasing level was ‘Breeze Yellow’, ‘Rainbow Rosy’ and ‘Splash Sweet’. After 20 days Cd treatment, the content of MDA began to increase compared with control group. The content of MDA in ‘Breeze Yellow’ didn’t increased when the concentration of Cd lower than 2.5 mg/L, which showed the lowest increasing level, followed by ‘Splash Sweet’ and ‘Rainbow Rosy’.(4) The Cd enrichment condition in ‘Breeze Yellow’, ‘Rainbow Rosy’ and ‘Splash Sweet’. The Cd concentration in root and shoot of 3 chrysanthemum cultivars increased gradually with the increase of the Cd treatment concentration, and the Cd concentration in root was higher than shoot. The root BCF was highest in ‘Breeze Yellow’, followed by ‘Rainbow Rosy’>‘Splash Sweet;the shoot BCF was highest in ‘Breeze Yellow, followed by ‘Splash Sweet’> ‘Rainbow Rosy. The TF of 3 cultivars increased Firstly, then decreased with the increase of Cd concentration. The TF was highest in ‘Breeze Yellow’, followed by ‘Rainbow Rosy’ >‘Splash Sweet’. Therefore, ‘Breeze Yellow’ have highest Cd accumulation and translocation capability, followed by ‘Splash Sweet’> ‘Rainbow Rosy’.(5)Taking the growth indexes, physiological indexes, Cd toxic symptom, and Cd enrichment condition in consideration, ‘Breeze Yellow’ had strongest Cd-tolerance ability, followed by ‘Splash Sweet’> ‘Rainbow Rosy’.