问题 问答题 简答题

人参种子休眠?

答案

参考答案:

自然成熟的人参种子貝有休眠特性,自然条件下的休眠期可达21~22个月。研究发现,人参种子休眠属于综合休眠类型,分形态休眠和生理休眠2个阶段。

⑴形态休眠:收获的人参种子,其胚尚未发肓完成,在适宜温度和湿度下,后熟时间为3~4个月,当胚长达到或超过了胚乳长的2/3时才能度过形态休眠,适宜温度为15~20℃。

⑵生理休眠:人参种胚形态成熟后,给予适合种子萌发的温度和湿度条件,仍不能萌动出苗,这是由于人参种孑生理休眠的缘故。低温是人参种子度过生理休眠的必要条件,完成形态后熟的人参种子,在0~10℃条件下,60~70d才能通过生理后熟。

完形填空

第二节完形填空(共20小题;每小题1分,满分20分)

The night was dark, though sometimes the moving clouds allowed a star or two to be seen in the sky. The poor men held on to any bit of wood they could find. They called to the Marie (圣母玛丽亚) for  36 , but she was far  37  the reach of the human voice. At one o’clock in the morning, the water was getting  38 , and a strong  39  had begun to blow. Suddenly  40  were seen in the distance; another ship! The shouts of the swimmers were heard on board, and willing hands pulled them out of the water. The  41  of the ship that had so  42   arrived on the scene in time to save their lives was Ellen. What had brought her to the exact spot through the  43  and the pathless sea? Her captain had known  44  about the wreck (沉船) and had indeed attempted to sail away from it. But let him speak for himself.

“I was forced by the wind,” he said long afterwards, “to  45  my course (航道). Just as I did it, a small  46  flew across the ship once or twice and then  47  at my face. I took  48  of this until exactly the same thing happened at a   49  time, which caused me to think it rather  50 , while I was thus  51  it, the same bird for the third time, made its appearance and flew  52  in the same way as before. I was then  53  to change my course back to the original (原来的) one. I had not gone far  54  I heard strange noises; and when I tried to   55  where they came from, I found I was in the middle of people who had been shipwrecked (船只失事). I immediately did my best to save them.”

36. A. food       B. help       C. rest           D. stop

37. A. between    B. out        C. beyond          D. in

38. A. colder       B. deeper    C. saltier          D. warmer

39. A. smoke      B. wave      C. sand           D. wind

40. A. people     B. lights      C. ships          D. houses

41. A. name       B. owner     C. captain        D. person

42. A. slowly      B. early       C. immediately      D. fortunately

43. A. light        B. wind     C. darkness       D. water

44. A. everything   B. nothing    C. something     D. anything

45. A. continue    B. turn      C. change        D. sail

46. A. light       B. fish       C. plane         D. bird

47. A. flew       B. stopped    C. stayed         D. looked

48. A. no care     B. good care C. no notice       D. some notice

49. A. good       B. second    C. third          D. long

50. A. interesting   B. funny     C. common        D. unusual

51. A. searching   B. expecting   C. considering     D. hearing

52. A. back       B. about           C. up           D. down

53. A. decided     B. advised   C. persuaded      D. invited

54. A. when      B. while           C. as            D. after

55. A. listen to     B. search for C. make sure      D. look out

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