图形标注问题

Z=peaks;
h=plot(Z(:,33));
x=get(h,'XData');
y=get(h,'YData');
imin=find(min(y)==y);
imax=find(max(y)==y);
text(x(imin),y(imin),['Minimum=',num2str(y(imin))],'VerticalAlignment','middle','HorizontalAlignment','left','FontSize',14)
text(x(imax),y(imax),['Maximum=',num2str(y(imax))],'VerticalAlignment','bottom','HorizontalAlignment','right','FontSize',14)
str1(1)={'center each line in the Uicontrol'};
str1(2)={'Also check out the textwrap function'};
str2(1)={'each cell is a quoted string'};
str2(2)={'you can specify how the string is aligned'};
str2(3)={'you can use latex symbols like \pi \chi \Xi'};
str2(4)={'\bfOr use hold \rm\itor italic font\rm'};
str2(5)={'\fontname{courier}Or even change fonts'};
uicontrol('Style','text','Position',[80 80 200 30],'String',str1);
text(45,0,str2,'HorizontalAlignment','right')

为什么我运行时没有显示标注内容？还有第二行的Z(:,33)是什么意思？