关于组织培养，描述正确的有（）

A、繁殖系数较低，切面较大，易感染病毒病等病害

B、主要用于大量生产无病毒商品花卉，尤其是观叶植物和鲜切花

C、繁殖速度快，繁殖系数大，繁殖方式多，适用的品种多

D、其寿命的长短除与遗传特性和发育是否健壮有关外，还受环境因素的影响

相关问题推荐

• 共用题干
  Keeping Cut Flowers（鲜切花）
  1. While everybody enjoys fresh cut flowers around his/her house,few people know how to keep them for as long as possible .This may be done by keeping in mind a few simple facts.
  2. An important thing to remember about cut flowers is that they are sensitive to temperature.For example,studies have shown that cut carnations（康乃馨）retain their freshness eight times lon-ger when kept at 12℃than when kept at 26℃．Keeping freshly harvested flowers at the right tem-peratures is probably the most important aspect of flower care.
  3. Flowers are not intended by nature to live very long.Their biological purpose is simply to at-tract birds or insects,such as bees,for pollination（授粉）.After that,they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide（二氧化碳）, called respiration（呼吸）,generates the energy the flower needs to give the flower its shape and color. The making of seeds also depends on this energy.While all living things respire,flowers have a high level of respiration.A result of all this respiration is heat,and for flowers the level of heat relative to the mass of the flower is very high.Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration,the sooner the flower dies.
  4. How,then,to control the rate at which flowers die?By controlling respiration.How is respi-ration controlled?By controlling temperature .We know that respiration produces heat,but the re-verse（相反的过程）is also true. Thus by maintaining low temperatures , respiration is reduced and the cut flower will age more slowly.
  5. Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to“drink”water that is dirty or otherwise polluted.Even when water looks and smells clean,it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach（漂白剂）can be used in small quantities.It is recommended that 15 drops of chlorine bleach(at 4%solution)be add-ed to each litre of water. The water and solution should also be replaced each day.
  Respiration plays a key role________.
  A: by keeping its original shape and color
  B: in the life of cut flowers
  C: to produce carbon dioxide
  D: for as long as possible
  E: by controlling temperature
  F: to replace the water and solution every day

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• 水分是鲜切花植物生存的重要条件，在鲜切花栽培中无论什么鲜切花都一样浇水才能长得旺盛。

  A、对

  B、错

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• 下图示意的甲、乙两国分别为传统、新兴的鲜切花生产国。据此，回答1—2题。

  

  1、比较甲、乙两国降水特点及其原因  ①甲国受西风带和暖流影响，全年降水较丰沛且季节分配均匀  ②甲国受副热带高压带和西风带的交替影响，降水季节差异大  ③乙国受赤道低压带影响，全年降水丰沛且季节分配均匀  ④乙国受地形影响，降水季节差异大

  [  ]

  A、①③B、①④C、②③D、②④

  2、与甲国相比，乙国发展鲜切花生产的优势自然条件是  ①热量丰富②光照充足③地形平坦④水源丰富

  [  ]

  A、①②B、①④C、②③D、③④

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