x轴上的阿拉伯标签在jqplot jquery中重叠，如何解决？

Question

jqplot jquery中x轴的阿拉伯标签重叠，怎么办？
我编写以下代码

var plot1 = $.jqplot('chart2', [line1], {
  title: 'Crop Yield Charnge, 2008 to 2009',
  seriesDefaults: {
    renderer: $.jqplot.BarRenderer,
    rendererOptions: {
      waterfall: true,
      varyBarColor: true
    },
    pointLabels: {
      hideZeros: true
    },
    yaxis: 'y2axis'
  },
  axes: {
    xaxis: {
      renderer: $.jqplot.CategoryAxisRenderer,
      ticks: ticks,
      tickRenderer: $.jqplot.CanvasAxisTickRenderer,
      tickOptions: {
        angle: -90,
        fontSize: '10pt',
        showMark: false,
        showGridline: false
      }
    },
    y2axis: {
      min: 0,
      tickInterval: 5
    }
  }
});

enter image description here