| Camellia oleifera is an important woody oil tree species in the south of China.Rosmarinus officinalis is an excellent aromatic plant suitable for growing on the slope and between the lines of young forest of Camellia oleifera,it has the remarkable effect of soil and water conservation and pest control.However,it is not clear whether Rosmarinus officinalis has an adverse effect on the growth and development of Camellia oleifera.In view of this,this paper studied the allelopathy of Rosmarinus officinalis stem and leaf and rhizosphere soil water extract on Camellia oleifera,with the effect of intercropping of Camellia oleifera and Rosmarinus officinalis on soil enzyme activity of Camellia oleifera,to provide a reasonable basis for promoting the intercropping of young Camellia oleifera and Rosmarinus officinalis.The main results are as follows:(1)The components of stem and leaf and rhizosphere soil of Rosmarinus officinalis were identified by GC-MS.A total of 36 target substances were identified in the stem and leaf of Rosmarinus officinalis,including a large number of terpenoids and ketones.Eighteen types of effective substances were identified in the rhizosphere soil of Rosmarinus officinalis,including a large number of phenolic acids.Common substances in Rosmarinus officinalis stem and leaf and rhizosphere soil:D-Limonene,camphor,2,4-Di-tert-butylphenol,dibutyl phthalate,octadecanoic acid,n-Hexadecanoic acid.(2)The effects of Rosmarinus officinalis stem and leaf extract,and rhizosphere soil extract on the growth of Camellia oleifera were studied.Results showed that the low concentration of Rosmarinus officinalis extracts(25 g/L)promoted the most growth indexes of Camellia oleifera,such as plant height,ground diameter,leaf number and new shoot length,while the highest concentration(200 g/L)reduced the most growth indexes.(3)The effects of Rosmarinus officinalis extracts on photosynthetic index and chlorophyll fluorescence parameters in leaves of Camellia oleifera were studied.Results showed that the low concentration Rosmarinus officinalis stem and leaf extracts promoted chlorophyll content(Chla+b),net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)while the high inhibited these indexes.When treated with 100 g/L and 200 g/L rosemary extract,the intercellular CO2 concentration of Camellia oleifera increased significantly by 46.32%and 105.42%compared with the control(p<0.05).Different concentration of Rosmarinus officinalis rhizos-phere soil extract can restrain chlorophyll content(Chla+b),net photo synthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr)of Camellia oleifera and promote intercellular CO2 concentration.The higher concentration(100-200 g/L)of Rosmarinus officinalis stem and leaf extract had significant inhibition on its maximum fluorescence variable(Fm),actual photochemical quantum efficiency(?PS?),photochemical quenching coefficient(qp)and electron transport rate(ETR).(4)The effects of Rosmarinus officinalis extract on osmotic regulating substances and antioxidant enzymes in leaves of Camellia oleifera were studied.Results showed that at different concentration periods,the lowest(25 g/L)Rosmarinus officinalis extracts of stems and leaves and rhizosphere soil promote the soluble protein in leaves of Camellia oleifera.The contents of soluble sugar,soluble starch and proline in leaves of Camellia oleifera showed a tendency of decreasing first and then increasing under different concentration of stem and leave and rhizosphere soil extract of Rosmarinus officinalis.The malondialdehyde(MDA)content,SOD activity,POD activity and CAT activity of Camellia oleifera leaves increased to different degrees under different concentration of Rosmarinus officinalis stem and leave and rhizosphere soil extract.(5)The Effects of Rosmarinus officinalis extract on morphological and physiological indexes of Camellia oleifera root were studied.Results showed that the effect of stem and leaf extracts of Rosmarinus officinalis on the root length,total surface area and total root volume of Camellia oleifera was the lowest concentration promoting(25 g/L)other concentration inhibiting,but the effect on the average root diameter was the opposite,when treated with 50 g/L extract,the number of root tips of Camellia oleifera increased significantly by 15.22%compared with the control(p<0.05).The rhizosphere soil extract of Rosmarinus officinalis with different concen-tration had inhibitory effect on root length,total surface area,total root volume and root tip number,and promoted effect on root mean diameter.The extract of Rosmarinus officinalis stem and leaf and rhizosphere soil promoted the soluble protein content,the MDA,SOD,POD and CAT activity of Camellia oleifera root to different degrees.The content of soluble sugar and free proline in the roots of Camellia oleifera increased significantly under the treatment of 200 g/L Rosmarinus officinalis stem and leaf extract and rhizosphere soil extract.(6)The effect of Rosmarinus officinalis extract and Camellia oleifera Rosmarinus officinalis intercropping on soil enzyme activity of Camellia oleifera were studied.Results showed the extracts of the stem and leaf and rhizosphere soil of Rosmarinus officinalis promoted the activities of urease,acid phosphatase,catalase and sucrase of Camellia oleifera as a whole,the enzyme activity of soil with lower concentration(25-50 g/L)is higher than that of soil with higher concentration(100-200 g/L).In the top 20 cm soil layer,the activities of urease,acid phosphatase,sucrase and catalase in Camellia oleifera and Rosmarinus officinalis intercropping mode were higher than those in Camellia oleifera monoculture mode.(7)According to the grey comprehensive evaluation,Rosmarinus officinalis stem and leaf extract and rhizosphere soil extract can produce allelopathic effect on Camellia oleifera.25 g/L Rosmarinus officinalis stem and leaf extract and rhizosphere soil extract can produce positive allelopathy effect on Camellia oleifera.With the increase of the concentration of the extract,the allelopathy of Rosmarinus officinalis extract to Camellia oleifera gradually changed from positive effect to negative effect.The allelopathy of stem and leaf extract to Camellia oleifera was stronger than that of rhizosphere soil extract.(8)In order to improve the yield of Camellia oleifera,Rosmarinus officinalis with certain planting density can be mixed with Camellia oleifera by using allelopathy promoting effect of low concentration Rosmarinus officinalis extract on Camellia oleifera in actual production. |
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