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دانستنی های علوم - طرح ابتکاری برش گیری از بافت های گیاهی
دانستنی های علوم
رسیدن به اهداف بزرگ، جز با کسب علم امکان پذیر نیست. مقام معظم رهبری
پنجشنبه هفتم بهمن 1389

طرح ابتکاری برش گیری از بافت های گیاهی

پنجشنبه هفتم بهمن 1389

نوع مطلب :زیست شناسی، 
نویسنده :حمیده عالی

در دانشگاه ها جهت برش گیری از بافت های گیاهی، از دستگاه میکروتوم استفاده می کنند. به علت گران بودن این دستگاه، کم تر مدرسه ای را می توان یافت که آن را در اختیار داشته باشد. لذا دبیران و دانش آموزان نمونه را با دست نگه می دارند و یا آن را درون کائوچو می گذارند و به وسیله ی تیغ، برش می دهند؛ اما به علت لرزش دست، یا سفت بودن نمونه(ساقه) و یا عریض بودن(میوه)، برش حاصل فاقد کیفیت لازم است و چون دارای انحنا و حباب است، تصویر واضحی ایجاد نمی کند. تهیه ی برش مناسب، زمان زیادی را به خود اختصاص می دهد.

توضیح طرح ابتکاری:

1.دو عدد تیغ تهیه می کنیم. سپس پوشش خارجی هر دو (کاغذ معمولی روی آن) را بر می داریم.

2.پوشش داخلی (کاغذ مومی) تیغ اول را کاملاً بر می داریم تا تیغ برهنه شود. اما در مورد تیغ دوم فقط یک سوم از این کاغذ را جدا می کنیم و دو سوم دیگر را روی خود تیغ باقی می گذاریم.

3.دو تیغ را روی یکدیگر می گذاریم. در نتیجه بین آن ها فاصله ای در حدود 50 میکرون (به علت وجود کاغذ) به وجود می آید.

4.نمونه را درون ظرف آبی قرار می دهیم، به طریقی که آب همه ی نمونه را در بر گیرد.

5.دو طرف تیغ را با دو دست می گیریم و آن را روی نمونه می گذاریم و ضمن فشار دادن به سمت پائین، به سمت چپ و یا راست نیز حرکت می دهیم.

6.برش تهیه شده بین دو تیغ قرار می گیرد. و چون درون آب قرار داشته، به راحتی از تیغ جدا می شود. آن را به روی لام منتقل و یا مراحل رنگ آمیزی را طی می کنیم.

                                

مزایای طرح:

1-تهیه ی برش صاف و بدون انحنا

2-تهیه ی برش نازک

3-تهیه ی نمونه در کم ترین زمان(سه دقیقه)

4-امکان برش گیری توسط دانش آموزان

منبع:مجله رشد آموزش زیست شناسی شماره 72 ،سید جمال مساوات




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