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举例说明营养分配局限性在果树生产中的应用。

答案

参考答案:

分配的局限性指果树光合产物首先保证自身需要,如有富余则就近供应、蒹有同侧供应的现象。由此规律导致不同枝条类型营养特点的差异;一般长枝(营养枝)前期消耗多、后期光合产物生产也多、外运范围广,但运输量随距离增大而减少,其分布均匀对均衡树势意义重大;中枝只有季节性的调济作用;短枝则以自供为主。

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     Money, jewels and important documents (文件) are not the only valuables placed in banks these days.

  1   There're ten breast banks set up across the United States, where mothers can donate (捐赠) their extra

milk for other women's babies. Experts say breast milk is the best food for babies. The World Health

Organization says it is the only food that babies should get during the first six months of life, in most cases.

   2   Sometimes these premature babies (早产儿) must stay in hospital for many weeks. 

       3   Doctor James Cameron who treats newborns at Lutheran Children's Hospital in Fort Wayne, India

says:"The fact is that there are so many different proteins and specialized sugars in the breast milk that the

mom's able to make that help provide immunity (免疫).It's very important for the health of newborns. 

       4   Donors must be willing to provide almost three liters (公升) of breast milk. They freeze the milk

and take it to the station. There, employees warm the milk and mix it with other mothers' milk. Then, the

milk is heated to kill bacteria (细菌).After that, the technicians test samples of all the milk to make sure it is

safe and healthful. The milk is re-frozen and sent to the main milk bank. The milk bank transports the milk to

hospitals to feed premature or sick babies. To ensure the quality of the breast milk, donors must obey certain

requirements, too.   5   

A. More mothers are willing to donate breast milk.

B. Donors are not permitted to smoke tobacco, use illegal drugs or drink too much alcohol (酒精).

C. The working process (程序)is strict.

D. Some mothers store their breast milk in banks.

E. Breast milk is almost like medicine.

F. Breast milk is babies' main food.

G. Breast milk is especially important for babies born too early.

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