| Acacia cincinnata belongs to Acacia Mill, of Mimosaceae family.Originating in Australia, Papua New Guinea and Indonesia and other places, after the introduction of China in Guangdong, Guangxi, Fujian and other places to grow better. In this paper,Seeds of Acacia cincinnata as materials, treated by 60Co-γ ray radiation with 7 doses (OGy,200Gy,400Gy,600Gy,800Gy,1000Gy)treatment, observing and measuring their seed germination, seedling growth and morphology, chlorophyll content,protection of enzyme activities, chlorophyll fluorescence,etc.For biological mutagenic effects of Acacia cincinnata mutants,to selected mutants,to make the basic research on the further Acacia cincinnata mutation breeding. The main findings are as follows:1.Mutagenic effects of 60Co-y ray on Acacia cincinnata seed germination significantly, mainly in the low-dose radiation treatment 400Gy promoted seedling survival rate, root length increased, germination potential in the 200Gy treatment was slightly higher than that in the OGy treatment; higher dose treatment significantly inhibited seed germination, with the increase of radiation dose,the germination potential,height of seedling,root length and fresh weight showed a significant downward trend,early seedling different types and traits of mutation situations emergence increased.2.Different 60Co-γ rays irradiation on the growth morphology of adult Acacia cincinnata seedlings significantly, low-dose radiation on plant growth have a positive role in promoting,such as plant height,ground diameter,internode Iength,leaf Iength,leaf width,leaf area, leaf number,leaf weight increased, higher doses showed growth morphology of each index decreased significantly, mainly for plant type and leaf type of variation.3.The relative regression equation is determined by seedling survival rate:y= 1.0887-0.00061x, a correlation coefficient of 0.90725, to determine the Acacia cincinnata seeds irradiation dose is 965.1Gy, critical dose was 1129Gy, dose of 70% growth was 637.2Gy.It is known that the suitable radiation dose range is 637.2Gy-1129Gy.4.Different radiation on seedling roots, stems and leaves of antioxidant enzyme activities and MDA content have different effects,which the Acacia cincinnata leaves, roots and stems with SOD activities,MDA content showed similar trend. With the increase of radiation dose, Both were increased first and then decreased, Acacia cincinnata different parts of POD activities showed different fluctuation and the size of the order is:root>stem>Ieaf,and changes of CAT activities and PPO activities in different parts was different,in different does treatment by promoting or inhibiting,and high does radiation had greater impact.According to the correlation analysis,the SOD activity of root,stem and leaf was positively correlated with the radiation does,and the MDA activity was negatively correlated with the radiation does.5.Different radiation does treatment Acacia cincinnata leaf chlorophyll contents were significantly, compared to the 0Gy,200Gy irradiation treatment increased the content of chlorophyll;and the treatment of higher radiation (400-1200Gy) reduced the content of chlorophyll and the higher dose of chlorophyll content was lower.6.Different irradiation doses of chlorophyll fluorescence parameters Fo,Fm,Fv had not significant differences that was from low to high fluctuation trend,in 200Gy and 1000Gy,in 800Gy and 1200Gy respectively, toobtain two low peak and two hiagh peak; Different irradiation doses of chlorophyll fluorescence parameters Fv/ Fm,Fv/Fo had not significant differences,the two have the same change trend,low does 200Gy treatment group reached the highest value,high does treatment significantly reduced.7.The results of the leaf photosynthetic characteristics showed that different irradiation doses of Acacia cincinnata leaf photosynthetic characteristics have different significant effects, with radiation dose the increased,the trend of net photosynthetic rate was first increased and then decreased,respectively in 200Gy and 1200Gy made the maximum value and minimum value,with OGy treatment increased by 47.7% and reduced 52.3%; Transpiration rate and stomatal conductance were first increased and then decreased and increased gradually decreased after, were in 200Gy and 1200Gy radiation does achieved peak, the lowest value.The intercellular concentration was from low to high,and there was a certain does effect after the first decrease,and the maximum does was highest.8.The effect of 60Co-γ ray irradiation treatment on different traits was different.Through principal component analysis method,the germination rate,germination potential,seedling height,root length,enzyme activities,MDA content,survival rate,leaf traits, Fv/Fm,Fv/Fo, photosynthetic characteristics of 21 measurement index, Acacia cincinnata crassicarpa mutagenic effects of comprehensive evaluation of different irradiation does treatment.These results indicated that the dominant factor affecting the mutagenic effect of Acacia cincinnata were leaf traits, photosynthetic characteristics, germination potential, survival rate etc.In the comprehensive evaluation, the ranking order of each treatment does was 200Gy>400Gy>800Gy>OGy> 1000Gy>600Gy> 1200Gy.Then consider important degree of each principal component,growth traits,enzyme activities, photosynthetic characteristics etc,preliminary think the three does of 200Gy,400Gy,800Gy can be a very well response with 60Co-y rays to the mutagenic effects of Acacia concinnatai. |
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