708 Botanical Microtechnique 



nemata (Sax and Humphrey) . Make an acetocarniine smear of one 

 anther ot a flower to determine the stage ot meiosis. \\'hen the desired 

 stage is found, smear the sporocytes from a fresh anther on a per- 

 fectly clean slide. Immerse the slide, or flood the smear with ammonia 

 pre-treatment solution. This contains 1 % (concentrated) ammonium 

 hydroxide in S()^'( alcohol. Try pre-treatments of 10 to 30 seconds. 

 Drain, add a drop of acetocarniine and proceed as ^vith ordinary 

 smears. 



Smear preparations can be made permanent. If the cells were 

 smeared on clean glass, they will adhere during the subsequent treat- 

 ment. Many versions of the method may be foimd in the literature. 

 Essentially, the process consists of dehydrating the smear and mount- 

 ing in balsam or resin. Ihe schedule used by Sears is one of the 

 simplest. 



Slip the cover glass by immersing the slide in equal Aolmnes of 

 acetic acid and alcohol. One effective method is to in\ert the slide 

 in a Petri dish, with one end of the slide held up on a piece of glass 

 rod. The coxer glass slides off gently without dislodging the smear. 

 Pass the slide and its cover glass through the following fluids at 2-5 

 min. intervals: 



(1) eqiiiil volumes of etliyl and tertiary i)ulyl akoliol 



(2) tertiary butyl alcohol, 3 changes 



Place the slide with the smear upward on blotting paper, place a 

 drop of thin balsam or resin on the smear, and lower the cover glass 

 carefidly. Place a lead weight on the cover glass. 



A similar acetic acid-ethyl alcohol series can be used (McClintock) 

 but more intermediate gradations must be used to prevent collapse 

 of the sporocytes. 



The advanced xvorker can (ind additional deiails in ihe (oin- 

 prehensive review of acetocarniine methods by Smith (1947) , Avliose 

 bibli()gra])hy also gives citations of the workers xvhose names appear 

 in thr ])rcs(ni chapter. 



MACERATION 



Whole inounis or sections of tissue fie(]ueiuly do not convey an 

 adequate tlnce-dinunsional iinpicssion ol (cll sirutiure. A xaluablc 

 and much-neglected type of preparation is made by isolating com- 

 plete individual cells from a mass of tisstie. This is accomplished 

 by chemical and medianical sejiaration oi cells. 1 he separation takes 

 place along the middle lamella. Preliminai \ treatment of the tissues 

 is the same, regardless of the subseijuent maceration method. If the 



