Effects Of Chemical Root Pruning On Physostegia By Two Carbonates

The container nursery has become the important content of modern forestry, is also an important form of seedlings industrialization and a new way in developing efficient forestry. Currently the container nursery faces a problem,the longer the time plant in the container, the easier the roots coil, reason of which is, in the container, that the roots of plant all grow centrifugally and radially, when the roots hit basin wall, they will not turn back and distribute uniformly, but coil along basin wall, as a result, the roots knot densely in the basin, but roots inside the soil are few, the stem of seeding will be hurt when the lateral root coil around the main root(Bell, 1978), Thereby, it reducing the wind resistance of seedlings, and the demand of water and fertilizer can't be meet and high temperature in summer cause a great deal of high concentrated roots dead , finally cause plant grow badly. Therefore it is very important to resolving the problem of container seeding's roots coiled irregularly. We could use some chemical reagents as the root control agent to prevent the roots from coiling irregularly.For the problem above, we choosed copper carbonate, zinc carbonate as a root-controlled agent, latex paints as a reagent carrier to study the effects of two root control agents on potted Physostegia, in order to select the optimal root-controlled agent and make sure optimal dosage, evaluate the effects of the root-controlled agent on the plant growth, expect to provide a reference for the spread of root-controlled agent. Experiment was carried on mainly from the following aspects:(1)Studied the effects of reagent carrier on plant growth. The result showed that paint and latex paints had no effects on plant growth, the paint was prone to fall off, but non-woven could prevent plant roots from coiling irregularly to some extent.(2)Studied copper carbonate's effects of root-controlled on Physostegia, the result showed, copper carbonate with concentration of 120 g/L and 200 g/L had significant effect in the aspects of enhancing plant growth rate, copper carbonate with concentration of 120 g/L and 200 g/L could increase plant roots' weight effectively, shorten a plant root and increase the lateral root's quantity. However, there was very serious remnant of all kinds of reagent, and the higher the concentration, the more the remnant.(3)Studied zinc carbonate's effects of roots-controlled on Physostegia, the result showed, the zinc carbonate with concentration of 100 g/L could effective enhance the plant growth rate, but the zinc carbonate with concentration of 200 g/L and 300 g/L reduce the plant growth rate because of too high concentration; the zinc carbonate with concentration of 200 g/L and 300 g/L had significant effect in the aspects of increasing plant roots fresh weight and dry weight; the zinc reagent with concentration of 100 g/L, 200 g/L and 300 g/L could effective increase the roots' length, induce more lateral roots, which prevented the roots from coiling irregularly and enhanced the plant quality, but there was also very serious remnant of all kinds of reagent, and the higher the concentration, the more the remnant.