| Tung tree(Vernicia fordii(Hemsl.)Airy Shaw)is Chinese unique economic tree.It is an important species of industrial oil tree.Although the traditional method of tung oil harvesting is to wait for its full maturity to collect until its natural drop,but this way of harvesting will lead to mixed quality fruits and affect the development of high-end tung oil and its products.In addition,most of the tung oil fruit will fall off naturally after ripening,but some will not fall off,and the harvesting of these fruits needs the help of tools,which is extremely inconvenient.Dwarfed plants can solve these problems.This research adopts the different concentrations of multi-effect azole(PP333)and cycocel(CCC)seedling stage and tung reproductive respectively,respectively for the phenotypic traits,physiological and biochemical indexes,photosynthetic characteristics,economic characters,and fatty acid composition of further analysis,for choosing appropriate plants retardant dwarf tung provided the scientific basis,the main results were as follows:1.Effects of PP333 and CCC on the growth phenotype of tung tree seedlings:Under leaf spraying treatment with PP333 and CCC solutions of different concentrations,the seedling growth rate decreased with the increase of PP333 and CCC concentrations,but the effect of PP333 was more obvious.The seedling height growth amount of seedlings treated with medicated drugs was significantly smaller than that of the control.The increase of root diameter of seedlings increased with the increase of PP333 concentration and CCC concentration.Although there was a significant difference from the control group,there was no significant difference between the two groups.Comparatively,the thickening effect of CCC solution on the root diameter of seedlings was slightly stronger than that of PP333.Overall,the comparison of dwarfying effect was 1200mg·L-1PP333(d1200)>600mg·L-1PP333(d600)>1200mg·L-1CCC(a1200)>600mg·L1 CCC(a600).The results of seedling height and diameter in the following year showed that both PP333 and CCC had dwarfing persistence,but the effect was decreased compared with that of the treatment year.According to the rate of leaf deformity,the negative effect of CCC on the seedlings of pittosporum paulownia was higher than that of PP333,and the most obvious harmful effect was in the 1200mg·l-1 CCC group.2.Effects of PP333 and CCC on physiological responses of tung tree seedlings:In the spray treatment with PP333 and CCC solutions of different concentrations,the soluble sugar in leaves except a600 was slightly higher than that in the control group,which increased by 3.07%.The content of PP333 and CCC in the treatment groups decreased with the increase of the concentrations of PP333 and CCC,and was lower than that in the control group.The soluble protein content in leaves decreased with the increase of PP333 concentration,but increased with the increase of CCC concentration.The soluble protein content in a1200 group was 27.11%higher than that in the control group,while the soluble protein content in d1200 group was 84.04%lower than that in the control group.Although there was no significant difference in the content of malondialdehyde in the leaves of tung among the experimental groups,the content of malondialdehyde in the treatment groups was slightly increased compared with that in the control group.The SOD and POD activities of a1200 group were higher than those of other groups,and the SOD and POD activities of a1200 group were 20.27%and 25.09%higher than those of control group,respectively.3.Effects of PP333 and CCC on photosynthesis of pollination branches of young seedlings and adult trees of tung tree fortunei:In different concentrations of PP333 and CCC solution spray treatment,in terms of dealing with tung seedlings,600mg·L-1 multi-effect azole treatment group of photosynthetic parameters value is superior to other groups,while a1200 group was significantly lower than other groups,compared with control group,the net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci)and transpiration rate(Tr)numerical lower 14.31%,18.18%,1.75%and 14.96%respectively.From the chlorophyll fluorescence data,the variable fluorescence amount,PsII value and qP value in the PP333 treatment group were higher than those in the CCC treatment group,and the initial fluorescence amount and the maximum fluorescence amount in the a600 group were also higher than those in the CK group.SPAD value results showed that except for 1200mg·L-1 treatment group,there was no significant difference in the relative chlorophyll content of seedlings of tung between the treatment group and the CK group,the other three treatment groups were significantly higher than the control group.As for the mature pollination branches of tung,there were differences in the effects of PP333 and CCC on the photosynthesis of mature pollination branches of tung at different altitudes,among which PP333 with the concentration of 1200mg·L-1 had the most obvious difference compared with other groups.The photosynthetic effect of the 600mg·L-1 PP333 treatment group had the smallest difference compared with the CK group.4.Effects of PP333 and CCC on the phenotype,oil content and fatty acid composition of tung tree:After leaf spraying with different concentrations of PP333 and CCC solutions,fruit ripening was first in the PP333 group,then later in the CK group,and finally in the CCC group.The fruit diameter,longitudinal diameter and weight of d600 and a600 groups were not significantly different from those of the control group,but the indexes of d1200 and a1200 groups were significantly lower than those of the control group.High concentration PP333 and CCC directly sprayed on pollination branches could reduce the oil content of the fruit of tung tree,especially in the 1200mg·L-1 treatment group.Tung oil fatty acid detected a total of seven components:palmitic acid,stearic acid,oleic acid,linoleic acid,linolenic acid and paulonic acid(-paulonic acid and-paulonic acid).The relationship between oleic acid,linoleic acid and paulonic acid in tung oil was negatively correlated.The a600 group had the highest content of paulonic acid,but the content of-paulonic acid was significantly lower than that of the CK group(about 68.09%),and the content of-paulonic acid was significantly higher than that of the control group(about 16.15%),while there was no significant difference between the d600 group and the CK group.5.The relatively optimal method for seedling dwarfication of pittospora tomentosa was to apply 600mg·L-1 PP333 aqueous solution,which was sprayed twice in June and July respectively,with a one-month interval.The spray treatment on the leaf surface was based on the water droplets of the aqueous solution on each leaf. |
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