highchart IE8透明,该如何处理

highchart IE8透明
 如果设置IE8下的highchart图标的透明 我设置了
series:
                [{
                    name: '风级',
                    data: ArrayTop,
                    type: 'column',
                    shadow: false
                }, {
                    name: ' ',
                    data: ArrayButtom,
                    color: 'transparent',
                    //white
                    type: 'column',
                    shadow: false,
                    plotShadow: false,
                    tooltip: ''
                }, {
                    name: seriesName,
                    type: 'spline',
                    marker: {
                        symbol: 'circle'
                    },
                    color:'gray',
                    data: yyArray