Effect Of Seedling Strengthening Agent (SSA) By Self On Rapeseed (Brassica Napus L.)

A filed experiment was conducted to study the effect and its working mechanism of a new plant growth regulator(Seedling Strengthening Agent,SSA) on rapeseed from 2005 to 2007,with Huayouza No.6 and Zhongyouza No11(Brassica napus L) as the trail material.Criterion,such as chlorophyll content,soluble sugar and protein content,SOD and POD activities,seed yield and quality were employed to evaluate the effects.Results showed that:0.1%of T2(the second composition of SSA) ranked the first,and 0.1%of T3(the third composition of SSA) the second.What SSA worked were as follows:1 Enhanced seedling qualitySSA could enhance chlorophyll content,increase greenery number and collar diameter,reduce plant height and seedling diameter,making the plant compact,and ensuring rapeseed seedlings live through the winter safely.SSA increased chlorophyll content by 6.00%to 11.03%,greenery number and collar diameter by 2.49%and 3.50% separatelly.But plant height declined by 18.86%-22.28%and seedling diameter by 1.29%-6.10%.2 Increased the soluble sugar content in functional leaf of rapeseed during winterHaving applying SSA,the soluble sugar content increased at first and declined later. Three significant phases could be verified according to the dynamic changing sugar content.Soluble sugar content was lowed before DAT43 which declined by 8.5%and the content was increased gradually later which increased by 6.1%.That was beneficial to improve the cold resistance during the winter.Soluble protein content of seedling of rapeseed showed 5 cycles of up-and-down with 15days a period.But soluble protein content was reduced when treated by 0.1%of T2.3 Improved the ratio of C/N before winterC/N ratio was lower at first but higher later than the control.Four separate periods could be divided according to the curv.C/N ratio was lower before DAT43 declined by 8.8%(days after transplanting),which is good for vegetative growth of rapeseed seedlings. C/N ratio increased 32.4%after DAT43,and double-peak appeared around midwinter. 4 Increased the activity of some stress resistant related enzymesSOD and POD were considered the stress resistant related enzymes.Their activities in functional leaf of rapeseed showed a trend of being up at first but down later with a cycle of 10 days.SOD activity of 0.1%T2 and 0.1%T3 was higher than water control but lower than pp333 control in periods of DAT11-DAT47 and DAT74-DAT99.In the period of DAT47-DAT74,SOD activity was obviously lower than both control,but 0.1%T2＞0.1%T3.POD activity of 0.1%T2 showed complicated,while that of 0.1%T3 stayed between two controls.5 Increased the primary branches,main inflorescence length and collar diameter,but decreased initial branch heightSSA increased 17.32%to 19.32%of primary branches;8.87%of main inflorescence length and 6.1%to 18.03%of collar diameter.SSA decreased initial branch height by 17.08%to 19.64%.Reduction of initial branch height could advance the ability of lodging resistance.6 Increased pods per plant and 1000-grain weightSSA increased pods per plant by 11.91%to 19.28%,1000-gain weight by 4.92%to 5.98%.However,SSA decreased seeds per pod slightly by 0.67%to 1.34%.As pod per plant is one of the main yield components of rapeseed,and a most flexible factor as well, the increase of pods per plant could increase yield of rapeseed.7 Increased seed yieldSSA of T2 harvested 0.29t/hm~2 of seed yield,increasing 20.4%of the control and T3 followed with the yield of 0.27t/hm~2 increased by 11.5%in the first year trial.SSA of 0.1%T2 produced 0.31t/hm~2 of oilseed and 0.1%T3 got 0.29t/hm~2,increasing by 14.69% and 7.49%respectively.8 SSA could increase oil contentRapeseed quality was little affected by applying SSA.But,SSA could increase oil content(3.8%-4.9%) and protein content(about 2%).So oilseed quality could be improved.