| The plant mosquito abjection vanilla(Pelargonium×Citrenella)was a perennial aromatic grass,created by a Holland botanist through cell fusion of the Chinese lemongrass herb with Pelargonium graveolens.It belongs to the family of Geraniacea,and to the genus of Geranium.Its life cycle is about 8 years.The plant not only repells mosquitoes and freshes the air,its leaves also looks tender,soft and evergreen,and thus beautiful in shape.They are excellent ornamental plants indoors and have considerable economic value.Up to the present,many studies have been conceritrated on the cultivation,propagation of the normally infertile plants,and also the mosquito repelling effectant citronella and its effects.Very little reports have been seen so far in its physiological and biochemical aspects.In this paper,several important physiological and biochemical constituents(soluble protein and sugar,malonyl dialdehyde),the content of reactive oxygen species(superoxide radical,hydroxyl radical and hydrogen peroxide)and its generating abilities,antioxidant enzyme(superoxide dismutase,peroxidase,catalase,ascorbate peroxidase,glutathione reductase)activities and zymograms of SOD,POD and CAT,as well as several antioxidant nonenzyme substances(ascorbic acid,glutathione and VE),of different plant parts(young,mature and ageing leaves/stems,and roots),were systematically measured and analyzed,in a hope to fill the blank,and to provide the basis for further research and development of this economically important ornamental plants.Results are as in the following.1 The Difference of the content of MDA,soluble protein and sugar in different plant parts of Pelargonium×CitrenellaThe MDA contents in different plant parts show the trend:young leaves(stems)＜mature leaves (stems)＜ageing leaves(stems).In the ageing yellow colored leaves and lignified stems,MDA content increased significantly.The contents of soluble sugar show the trend:young leaves (stems)＞mature leaves(stems)＞ageing leaves(stems).And soluble sugar content in the leaves was higher than that in the stems as a whole.As for the content of soluble protein in different parts of plant parts,no clear difference has been observed.Thus it can be seen that MDA content and soluble sugar content in young leaves(stems),mature leaves(stems),ageing leaves(stems)are inversely correlated. 2 The difference in the activities of antioxidative enzymes in different plant parts of Pelargonium×CitrenellaSOD activity has a trend of young leaves(stems)＞mature leaves(stems)＞aging leaves(stems), with a higher activity in leaves than in the stems as a general role;It also can be seen that SOD activity in stems decreases with the degree of lignification.POD activity also has a trend of young leaves＜mature leaves＜aging leaves,but no clear trend in the stems except that activity in aging stem increased significantly.CAT activity has a trend of mature leaves(stems)＞ageing leaves(stems)＞young leaves(stems), with CAT activity in stems generally higher than those in the leaves.CAT activity in roots,ageing leaves and young stems are considerable.APX activity is highest(13.3930 U·g-1·min-1)in ageing stems,while in the roots the lowest (3.2903 U·g-1·min-1).CAT activity has a trend of ageing stem＞young items＞mature leaves＞mature stems＞ageing leaves＞young leaves＞roots.GR activity CAT activity has trends of mature leaves＞roots＞ageing stems,and mature leaves (sterns)＞young leaves(stems)＞ageing leaves(stems).From the above,it can be seen that SOD is the key anti-oxidative enzyme in young leaves (stems)and roots.In mature leaves and stems CAT plays a relatively important role,while in the ageing/lignification the activity of POD and APX is relatively higher than in other plant parts.GR has a very low activity in mosquito abjection vanilla.3 The difference of generating reactive oxygen species of different plant parts of Pelargonium×CitrenellaThe rates of superoxide radical generation show that ageing leaves＞young stems＞mature leaves＞young leaves＞mature stem＞ageing stems＞roots。The contents of superoxide radical show a trend of leaves＞stems＞roots.The rates of hydroxyl radical generation show that ageing leaves＞mature leaves＞mature stems＞young stems＞ageing stems＞young leaves＞roots.The rates of hydrogen peroxide generation show that ageing leave＞mature stems＞mature leaves＞ageing stems＞young leaves＞young stems＞roots.These show that generally the rate of hydrogen peroxide generation increases with the maturing and ageing of tissues.4 The difference of the contents of antioxidant nonenzyme substances in different plant parts of Pelargonium×CitrenellaThe contents of ascorbic acid and VE were both the highest in mature leaves,very significantly higher than in other parts.Total antioxidant ability analyses show that leaves＞stems＞roots;and in leaves,ageing leaves＞mature leaves＞young leaves;in stems,mature stems＞young stem,ageing stems;the total antioxidant ability in root was low,considerable with that of ageing stems This trend is in good conformance with the difference of the rates of reactive oxygen species generation 5 Antioxidative zymogram analyses of different plant parts of Pelargonium×CitrenellaPolyacrylamide gel electrophoresis and activity staining showed that there are all together 5 bands (A1～A5)of SOD in all the plant parts,among which three bands(A2,A3 and AS)are strongly stained,and together with the relatively weak-stained A4,constitutes the 4 common bands of SOD in all plant parts.In young and mature leaves there are 4 bands(A2～A5),lacking the A1 band,which characteristically appeared in the ageing leaves.Judging from the zymogram,it can be seen that roughly SOD activity:young leaves＞mature leaves＞ageing leaves,in conformance with the foregoing activity measuring results.In stems and roots,no characteristic bands have been seen.No evident difference in activity wa observed in the different stems and roots.The POD zymogram shows that there are all together 7 bands(A1～A7),among which 4 bands (A2,A3,A6 and A7)are strongly stained;in leaves,young leaves have 4 bands(A1,A2,A6 and A7),only one strong band(A6),the others very weak;The number of bands in mature and ageing leaves are identical,7 bands(A1～A7),with considerable activity with one another but much stronger than those in young leaves;7 bands was observed in roots,with A2,A3 and A6 being the strong bands and the others,weak bands. |
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