| Randomized block design is applied in this experiment,Eucalyptus grandis×E.urophyllaNO.9 and E.urophylla×E.camaldulensis Dehnh as experi-mental material.In acidicic conditions,each root chamber aluminum phosphorus effect between different processing of each treatment of two clones Eucalyptus seedlings growth,seedling root morphological indicators,seedling antioxidant physiological characteristics,seedling root,stem and leaf of phosphorus and aluminum content and seedling photosynthetic physiological characteristics were studied.The conclusions are as follows:(1)Growth aspects:relative to deal with D(0.02 gP/L in split-root 1;0.12 gAl/L in split-root 2),with C(0.02gP/Lsplit-root 1;0.08gP/L+0.12gAl/L split-root 2)and B(0.1gP/L in split-root 1;0.12gAl/L in split-root 2)significantly increases the plant height of two Eucalyptus,deal with the phosphorus in the river sand in C and aluminum precipitation reaction AIPO4,reduce the activity of aluminum.Under the stress of aluminum,the addition of sufficient phosphorus(0.1gp/L)in treatment B directly into Eucalyptus also contributed to the growth of Eucalyptus.The plant height and diameter increment of E.urophylla × E.camaldulensis Dehnh were lower than that of E.grandis×E.urophylla NO.9.(2)Root morphological indicators:compared with treatment D,sufficient P supply in treatment B can increase the root growth of Eucalyptus under aluminum stress.The inhibition effect of aluminum stress on root growth of E.urophylla×E.camaldulensis Dehnh was more significant than that of E.grandis × E.urophylla NO.9.(3)Antioxidant physiological characteristics:compared with treatment B,phosphorus in treatment C reacts with Al in split-root 2 to form precipitation,which reduces the activity of A1 in river sand and alleviates aluminum stress.Treatment C alleviated the aluminum stress of E.urophylla×E.camaldulensis Dehnh,resulting in lower free proline content and SOD activity than treatment B with the same A1 and P concentrations.E.urophylla×E.camaldulensis Dehnh was more sensitive to A1 stress.(4)Phosphorus and aluminum content:compared with treatment D,treatment A(0.1 gP/L in split-root 1;0gAl/L in split-root 2)and treatment B with sufficient phosphorus(0.1 gP/L)can increase the total phosphorus content of eucalyptus.The absorption capacity of E.grandis×E.urophylla NO.9 is stronger in the underground part.E.urophylla×E.camaldulensis Dehnh is more easily enriched with aluminum in the aboveground part and E.grandis×E.urophylla NO.9 is more easily enriched with aluminum in the underground part.The two Eucalyptus seedlings have higher capacity to absorb aluminum in the underground part than in the aboveground part.(5)Photosynthetic physiological characteristics:compared with treatment D,sufficient P supply in treatment B under aluminum stress can promote the growth of Eucalyptus and increase its chlorophyll content,thus increasing the absorption and utilization efficiency of light energy in Eucalyptus.Compared with treatment D,the total chlorophyll content of E.urophylla×E.camaldulensis Dehnh treated with A(0.1 gP/L in split-root 1;0gAl/L in split-root 2)was significantly higher.In general,there was no significant difference in chlorophyll content between E.urophylla×E.camaldulensis Dehnh and E.grandis × E.urophylla NO.9.Fv/Fm did not respond strongly to aluminum stress on Eucalyptus.The light energy absorption and conversion efficiency of E.grandis×E.urophylla NO.9 is higher than that of E.urophyll×E.camaldulensis Dehnh.(6)Seedling quality index:treatment A is most beneficial to the growth of each treatment of two clones Eucalyptus seedlings.The quality of treated B seedlings was higher than that of treated D,indicating that the addition of P element could alleviate the Al stress on Eucalyptus trees.(7)Given the research in this paper,phosphate fertilizer can be applied through leaf surface fertilizer or nutrient bag of tree trunk in the future,which can avoid P fertilizer being fixed by Al in the soil and improve the utilization rate of P fertilizer. |
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