2014-2015学年高中英语 参考阅读 Pitcher plants素材 新人教版选修9

Pitcher plantsTropical Pitcher plants are impressive plants, needing humidity and warmth. They can divided into two main groups - highland plants, and lowland plants, but there is some cross over where you find the intermediate ones. The produce two typed of trap - lower traps formed on lower growth, and upper pitchers formed when the plants get larger and start to climb. The lowland plants like temperatures of around 25oC all the time, with a slight drop in temperature at night. They are very intolerant of low temperatures (we have lost many to a power cut in the winter!) They also like humidity of 80% ideally. These things need to be quite constant, so monitoring is important. If you don't have suitable tropical greenhouse, a terrarium can be a good place to grow lowland plants, though they may well out grow it. All Nepenthes can be pruned of they get too big. Highland plants like a fluctuation in temperature, particularly between day and night. Ideally it should be 20oC during the day, and 15oC at night, but some will tolerate temperatures just above freezing at night. Humidity should be no less that 60%. Many highlands will grow well on a windowsill, the back of a conservatory or in a shower room, but grow well in a warm greenhouse. Nepenthes like good light, but not the baking sun. They benefit from artificial lights in the winter as our days are so short. If grown in a greenhouse, 50% shade is needed. Watering Do not place in water trays. Water from the top and make sure they stay damp. Mist regularly -at least daily. This is very important, as humidity helps trap formation. If the tips of the leaves are drying before they produce traps, they need more humidity. Pla...