我观察昙花一现
<p>今天课堂上听老师说昙花是在于晚上九点左右开花的，太有意思，我想观察看看。</p><p><span word="Today">Today</span>, <span word="in">in</span> <span word="class">class</span>, <span word="I">I</span> <span word="heard">heard</span> <span word="the">the</span> <span word="teacher">teacher</span> <span word="said">said</span> <span word="that">that</span> <span word="Epiphyllum">Epiphyllum</span> <span word="blooms">blooms</span> <span word="around">around</span> 9 <span word="p">p</span>.<span word="m">m</span>., <span word="which">which</span> <span word="is">is</span> <span word="very">very</span> <span word="interesting">interesting</span>. <span word="I">I</span> <span word="want">want</span> <span word="to">to</span> <span word="observe">observe</span> <span word="it">it</span>.</p><p>我家恰好有种一盆昙花。为什么昙花不只白天不开花，到了深夜也不开花。我跑去问爸爸，昙花为什么只能“一现”呢？</p><p><span word="My">My</span> <span word="family">family</span> <span word="happens">happens</span> <span word="to">to</span> <span word="have">have</span> <span word="a">a</span> <span word="pot">pot</span> <span word="of">of</span> <span word="Epiphyllum">Epiphyllum</span>. <span word="Why">Why</span> <span word="don">don</span>'<span word="t">t</span> <span word="Epiphyllum">Epiphyllum</span> <span word="bloom">bloom</span> <span word="not">not</span> <span word="only">only</span> <span word="in">in</span> <span word="the">the</span> <span word="daytime">daytime</span>, <span word="but">but</span> <span word="also">also</span> <span word="in">in</span> <span word="the">the</span> <span word="late">late</span> <span word="night">night</span>. <span word="I">I</span> <span word="ran">ran</span> <span word="to">to</span> <span word="my">my</span> <span word="father">father</span> <span word="and">and</span> <span word="asked">asked</span> <span word="why">why</span> <span word="Epiphyllum">Epiphyllum</span> <span word="can">can</span> <span word="only">only</span> <span word="be">be</span> <span word="a">a</span> <span word="flash">flash</span>?</p><p>爸爸思索一下，耐心地对我说，“昙花是属仙人掌科植物。茎、叶都已发生了变态，老茎呈圆柱形且木质化，茎上有一层蜡质；叶子已退化成很细的针状。昙花的开花季节一般在6至10月，开花的时间一般在晚上8～9点钟以后，盛开的时间只有3～4个小时，非常短促。 昙花原产于中南美洲的热带沙漠地区，那里的气候特别干燥。白天气温非常高，娇嫩的昙花只有在晚上开放才能避免白天强烈阳光的烤灼，而昙花又属于虫媒花，沙漠地区晚上8、9点钟正是昆虫活动频繁之时，所以，此时开花最有利于授粉。午夜以后，沙漠地区气温又过低，不利于昆虫的活动，就不利于昙花的授粉。昙花开花时间短可以减少水分的丧失。因此，昙花在漫长的进化过程中逐渐形成了这种特殊的开花习性。”哦，原来是这样。我从此更加细心护养昙花。</p>
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