GENERAL TECHNIQUES FOR CLASSES OF PLANTS 717 



1412. Nebel's Lacmoid-Martius Yellow Method {Stain Tech., vi, 

 1931, p. 27). Crushed or sectioned fresh material is stained in a 

 mixture of 5 mgm. lacmoid and 5 mgm. martins yellow dissolved 

 in 10 to 15 c.c. water, adjusted to pH 8 by the addition of a few 

 drops of 1 per cent, ammonia, thus making the fluid deep olive- 

 green. After two to Ave minutes the material is mounted in the 

 stain or in water of the same pll. To make permanent mounts 

 fix crushed, dissected or otherwise prepared material in Carnoy 

 and transfer through 70 per cent, alcohol to alkaline water. Wash 

 thoroughly in tap-water to remove all acid or excessive alkali. 

 Stain one to five minutes and dehydrate rapidly in alcohols 

 containing lacmoid in solution in its blue modification {pH 8). 

 Mount in cedar oil and seal, or in balsam after clearing with 

 xylol. 



1413. Watkin's Cotton Blue-Lacto-phenol Method (Jot^m. Genet, 

 XV, 1925, p. 340). Originally applied to wheat, the technique is 

 applicable to all Gramineae. Note a flower being self-fertilised, 

 take the spike into the laboratory, place it in water and leave 

 for one hour. Dissect out the feathery style and stain and mount 

 in a 0-08 to 0-1 per cent, solution of cotton blue in lacto-phenol 

 (equal parts of lactic acid, phenol, glycerin and water). Over- 

 staining begins in one to four months ; stronger solutions are 

 unsatisfactory. 



AiYANGAR {Agric. and Live-stock in India, i, 1931, p. 471) uses 

 lacto-phenol for studying pollen-tube entry into the cotton ovule. 



