71G GENERAL TECHNIQUES FOR CLASSES OF PLANTS 



1410, Pollen Tubes in Style. Pistils should be artificially 

 pollinated and collected after an interval. They should be 

 collected in small phials and kept from drying out by the addition 

 of a drop of water. Slender styles and ovaries may be crushed 

 and fixed on the slide ; larger ones are first sectioned longitudinally 

 by hand. Styles fixed whole should be split longitudinally to 

 permit easier freeing from air with a vacuum pump. A dilute 

 solution of anilin blue stains the pollen-tube walls readily. 



BucHHOLz and Blakeslee {Science, xl, 1922) scald styles 

 of Datura in hot (not boiling) water for two minutes, slit lengthwise 

 and dissect away the cortical tissue. Stain the central core in 

 magenta (acid red), wash a little in water, clear in lactic acid, 

 mount whole in concentrated lactic acid and seal. Pressure 

 applied to the coverslip spreads the material in a thin layer. 

 The pollen-tubes show as dark red streaks among the elongated 

 pink cells of the conducting tissues. The stain improves in 

 twelve to twenty-four hours. 



BucHHOLZ {Stain Tech., vi, 1931, p. 13) has further developed 

 the technique. Artificially pollinated pistils are kept at 18° to 

 22° C. Styles are split along two sides, scalded half to two minutes 

 in water at 70° to 75° C. and killed by immersion several hours 

 in 50 per cent, alcohol containing 6 per cent, of formalin. Within 

 twelve hours of killing, dissect the cortex from the style and 

 stigma under a wide field binocular microscope. Stain the central 

 strand within twenty-four hours of dissection in a mixture of 

 8 parts 1 per cent, aqueous acid fuchsin and 2 parts 1 per cent, 

 aqueous alcoholic light green for three to six hours or overnight 

 if stain not too concentrated. Clear several hours in 80 per cent, 

 lactic acid, carefully spread out on slide and mount in lactic acid. 

 Seal after a few days with xylol damar or paraffin wax and gum 

 mastic. 



See also Buchholz and Blakeslee, Mem. Hort. Soc, N.Y., 

 iii, 1927, p. 245. 



1411. Chandler's Aceto-carmine and Magenta Method {Stain 

 Tech. vi, 1931, p. 25). Pistils are collected and immediately 

 killed in a mixture of 6 to 7 c.c. formalin in 100 c.c. 70 per cent, 

 alcohol. They may be examined at once or stored. Those with a 

 central canal are split longitudinally with needles along one side 

 to the central canal and the cut surfaces spread apart. Solid 

 styles are sectioned longitudinally freehand. Place a drop of 

 aceto-carmine (saturated solution in warm 45 per cent, acetic 

 acid) on the exposed surfaces. After a few seconds, add a drop 

 of saturated aqueous magenta. Remove excess stain with blotting 

 paper. Destain by passing absolute alcohol over the style and 

 absorbing it at the basal end with blotting paper. If tissue 

 differentiation is difficult, add a drop of anilin blue just before 

 the magenta. 



