Study On Induced Effects Of ORYZALIN Treatments On Tetraploid Watermelon

Three diploid watermelon[Citrullus lanatus Matsum &Naki] were treated by using ORYZALIN In manner of seedling dropped, seeds soaked and cotyledon regeneration for tetraploid inducement, Tetraploid variants and diploid on morphological traits were compared and discussed. The result were as follow.1,Seedling dropped and seeds soaked: (1) Three watermelon varieties were treated by ORYZALIN which concentration were 12.1mg/L,17.3mg/L,34.6mg/ L respectively. The time of seedling dropped were 2,4 and 6 days. The results showed that: Different concentration of ORYZALIN in three varieties all have worked on inducing tetraploid. The frequencies of tetraploid variant treated by seedling dropped in 6 days were over 15%. The highest was up to 25.2%, and the frequencies tetraploid variant treated as same manner in 4, 2 days were separately 4.7% to 20.9%, 2% to 13%. The time and the concentration was the important factor for tetraploid inducement(.2)Seeds of three watermelon varieties were soaked by ORYZALIN in concentration of 12mg/L,17.1mg/L,34.2mg/L in 10 hours; The result showed that: there were only one tetraploid plant among three varieties(No.S555)under 34.6 mg/L concentration,The variation frequencies was 1.7 %.The method of seedling dropped was better than seeds soaked for inducing tetraploid .2,The comparison of the morphological traits between induced tetraploid and diploid plants: (1) Pollen, The observation showed that there were significant variations in pollen's shape,size and the number.(2)Guard cells :The were larger and the number of stoma per unit leaf area was decreased with increasing ploidy. The length of diploid guard cells were about 25-26μm, and The length of diploid guard cells were about 34-36μm. (3) Seeds ;Compared tetraploid with diploid in seed length , width and seed exit ,It showed that the width of seed and seed exit were obviously wider, The length of seed were not significant.3,Establishment of the diploid watermelon regeneration system and effects of ORYZALIN on callus differentiation. The basic medium was MS, and it containing 6-BA,KT and IBA, The effect of different hormones concentration on watermelon cotyledon regeneration system were studied. The results showed that 6-BA was the most important factor for callus induction, The optimum concentration was 2.5-3.0μm/L. MS medium supplemented with kT0.03μm/L could obviously stimulate bud proliferation. In the cotyledons regeneration, as different concentration ORYZALIN were added into the medium used for each stage of tissue culture in order to induce adventitious shoot. The results showed that different concentration ORYZALIN could restrain the cotyledons and cotyledons differentiation. A few cotyledons which have been produced also can stop grow.