ExtJS4 刷新树中到某一个节点

ExtJS3中有Ext.tree.TreeLoader中有load(Ext.tree.TreeNode)方法能实现刷新树中的某个节点的功能，在Ext4中怎么实现呢？查了好多文档都没有找到好到方法!

现在的
TreeStore.load({
 node: xxx
})

参考部分treestore源码：
JScript code

load: function(options) {
        options = options || {};
        options.params = options.params || {};
        
        var me = this,
            node = options.node || me.tree.getRootNode(),
            root;
            
        // If there is not a node it means the user hasnt defined a rootnode yet. In this case lets just
        // create one for them.
        if (!node) {
            node = me.setRootNode({
                expanded: true
            });
        }
        
        if (me.clearOnLoad) {
            node.removeAll();
        }
        
        Ext.applyIf(options, {
            node: node
        });
        options.params[me.nodeParam] = node ? node.getId() : 'root';
        
        if (node) {
            node.set('loading', true);
        }
        
        return me.callParent([options]);
    },