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$WI LD R LATI\IES CROP PLANTS IN INDIA$

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48 THE BRITISH SMUT FUNGI 8eed treatment when there is mycelium in the embryo. Hot water. Wheat grain is soaked in cold water for four hours, drained for a few minutes, and submerged in warm water (52°-54° C.) for ten minutes^ It is then quickly spread in a thin layer to dry. For barley, the grain, after soaking, is plunged in water at 49° C. for five minutes and'then steeped for ten, minutes in water at 51° C. If the temperature is allowed to rise above 55° C. the grain may be damaged (Moore, 1945). Automatic machines for this treatment have been designed and some authors prefer a longer soaking (say, six hours) at a lower temperature (43° C.) (Jones, 1939). The injury to germination and growth which may foUow even careful treatment depends largely on the condition of the pericarp and this varies in each lot of seed (Tapke, 1924). Modifications of this method which make direct use of solar energy have been devised in India. No thermometer is necessary. Grain is soaked in water from 8 a.m. to 12 noon and exposed in a thin layer to the sun from noon to 4 p.m. The best months for treatment in the Punjab plains, where the method has been widely used, are Mayand June, when the temperature in sunshine reaches 131°F. The treated grain can be stored without deterioration and complete control of smut was obtained when untreated samples gave 5-12 per cent, of smut (Luthra & Sattar, 1934; Luthra, 1941). The hot-water treatment is applicable to other smut diseases transmitted by infected seed or other organs of the plant. Bulbs of the grape hyacinth carrying mycelium of V. vaillantii held for one hour in water at 110° F. yielded smut-free flowers in the following year (A. Smith in litt., 1947). Seed treatment when infection comes from the soil. In Britain the only soUbotne smut disease for which control is practised is onion smut. The soU remains contaminated for some years, and in view of the serious nature of the disease the wisest plan is to avoid planting onions or related crops in ground infested by Urocystis cepulae. Where this is not practicable the best method is to apply formaHn to the soil. After sowing the seed and before covering it with soil, formalin (40 per cent.) solution (one pint in 16 gals, of water) is trickled into the drill. This quantity wiU suf&ce for 800 yds. of drill. If the soil is unduly wet, a stronger solution (up to two pints) can be used with safety (Minist. Agric. & Fish. Advisory Leaflet 261). This method gives only partial control but it is more effective than organomercury dusts (Gibbs, Bayliss, & Blackmore, 1941). Experiments have been made also with organic sulphur dusts such as thiosan, arasan, and tersan. The results are conflicting, but on the whole these substances are less effective than the standard formahn drip method (Miller & McWhorter, 1945; Nelson, 1946). Attempts have been made to combine the fungicide with an excipient such as feldspar, which is used in conjunction with methyl ceUulose solution to coat the seed. Pelleted seed, which is larger and more uniform in shape, can be sown with greater precision and thinning is less laborious, but no method yet devised gives complete control of smut (Gorenz & Walker, 1947; Linn & NewhaU, 1948). FIXATIVES Flemming's weaker solution (Harper, 1899; Paravicini 1917; Bhzzard 1926; Seyfert, 1927; Kniep, 1921; Hanna, 1929; C. S. Wang, 1943) Bouin's,
TECHNIQUE 49 Allen's, modification of Bouin's (Seyfert, 1927; Evans, 1933, 1937), and Nawaschin's (D. T. Wang, 1934; Western, 1936 b) fixatives have been used for smuts. A method for demonstrating nuclei in the promycelium first used by Kniep (1921) has been adopted with only slight modifications. The following details are taken from Hanna (1929). A thin film of 1 per cent, malt agar is spread over a sHde and spores are dusted on the surface with a camel's-hair brush. The slides are inverted over glass rods in a Petri dish containing a few drops of distilled water. At the desired stage of germination the material is fixed in Flemming's weaker fluid (15 minutes). The fixative is removed by adding a few drops of distilled water and sucking up the excess liquid with filter-paper. To avoid washing off the spores during staining the sHdes are passed through a bath of ether and then into a 0-2 per cent, solution of collodion made up with equal parts of alcohol and ether. Others (Harper, 1899) have germiaated the spores in beerwort in a watch glass, and used egg albumen to fix them to the shde. The liquid, which should be turbid with germinating spores, is taken up in a fine capillary tube and discharged into a larger droplet of the fixative. The spores settle on the film of egg albumen, and the hquid is allowed to evaporate, but not to dry out completely, before the shde is passed on to the alcohols. The fixative is not washed out. For a study of the cytoplasm D. T. Wang (1934) found the best fixative was le Regaud, consisting of 3 per cent, potassium bichromate (four parts) and 40 per cent, commercial formalin (one part). STAINS Harper (1899) used the triple stain^ for nuclei in the promycehum, but found a 1 per cent, solution of methyl green better for staining nuclei in spores already in possession of a thick wall. Most workers since Harper have used Heidenhain's haematoxylon. No recognized technique exists for treating the nuclei of smuts with a quick-acting fixative followed immediately by acetocarmine or similar dye, as in the method used for pollen and macerated tissue. In preliminary tests at Aberystwyth dividing nuclei in the promycelia of U. hordei were stained red by lacmoid,^ and this type of reagent deserves further trial for the nuclei of smuts. Metachromatic granules in the vacuome have been demonstrated by means of' neutral red, cresyl blue, and Delafield's haematoxylon. AniUne fuchsin, with a counter-stain of light green, stained the chondriosomes bright red in material fixed in Meves reagent (Yen, 1937). For detailed observations on parasitic mycelium sections of plant tissue should be 3-5 /x. Triple and Heidenhain's were used by Blizzard (1926), safranin and fast green by Evans (1933) for Urocystis cepulae, thionin and orange G for Ustilago may Ms by Walters (1934). The general distribution of mycelium in the host can be demonstrated in hand sections of material fixed in 70 per cent, alcohol and stained by lactophenol cotton blue or in microtome sections, 10-12 /^t, by aniline gentian violet wjth a counter-stain of Bismarck brown. Take the slides from 70 per cent, alcohol and ^ For stains and fixatives see Plant Microtechnique, Johansen. McGraw-Hill, 1940. ^ See The Handling o/ Chromosomes, C. D. Darlington & L. F. La Cour. Allen and Unwin, 1942. 165 pp. D
Page 1 and 2: THE BRITISH SMUT FUNGI ^ (USTILAGIN
Page 3: FOREWORD THIS volume was started wh
Page 6 and 7: 6 PBEFACE We also acknowledge the b
Page 9 and 10: INTRODUCTION THE smut fungi, which
Page 11 and 12: INTRODUCTION H of bushels of wheat
Page 14 and 15: FIG. 1. Vstilago avenae on Arrhenat
Page 16: ^^ THE BBITISH SMUT FUNGI Young hea
Page 19 and 20: BIOLOGY 15 less than the normal, in
Page 21 and 22: BIOLOGy 17 and united with it, fina
Page 23 and 24: BIOLOGY 19 eermination in a collect
Page 25 and 26: BIOLOGY 21 genus, and the manner of
Page 27 and 28: BIOLOGY 23 species of Entyloma, and
Page 29 and 30: 3036^ BIOLOGY 25 in others. Dickins
Page 31 and 32: CYTOLOGY THE discovery of nuclei in
Page 33 and 34: GENETICS INCOMPATIBILITY KNIEP'S di
Page 35 and 36: GENETICS • 31 direction of growth
Page 37 and 38: GENETICS 35 when a few sporidia fro
Page 39 and 40: GENETICS 37 lines retained their di
Page 41 and 42: TECHNIQUE COLLECTION AND EXAMINATIO
Page 43 and 44: TECHNIQUE 41 be undesirable. Weak a
Page 45 and 46: TECHNIQUE 43 in one season (see p.
Page 47 and 48: TECHNIQUE 45 barley with loose smut
Page 49: TECHNIQUE 47 (1939), Holton & Heald
Page 53 and 54: CLASSIFICATION THE morphological ch
Page 55 and 56: THE BRITISH SMUT FUNGI MOST of the
Page 57 and 58: FIG. 2. Spore geimination in Ustila
Page 59 and 60: THE BRITISH SMUT FUJJGI 57 from one
Page 61 and 62: THE BRITISH SMUT FUKGI 59 of exsert
Page 63 and 64: THE BRITISH SMUT FUNGI 61 noticeabl
Page 65 and 66: THE BRITISH SMUT FUNGI 63 Evidence
Page 67 and 68: THE BRITISH SMUT FUNGI 65 winter in
Page 69 and 70: THE BRITISH SMUT FUNGI 67 Ustilago
Page 71 and 72: THE BRITISH SMUT FUlJGI 69 material
Page 73 and 74: THE BRITISH SMUT FUNGI 71 results o
Page 75 and 76: THE BRITISH SMUT FUNGI 73 TTstilago
Page 77 and 78: THE BRITISH SMUT FUNGI 75 Species i
Page 79 and 80: " TJSE BRITISH SMUT FUNGI 77 Ustila
Page 81 and 82: THE BKITISH SMUT FUNGI 79 On Carex
Page 83 and 84: THE BRITISH SMUT FUNGI 81 Exsiccati
Page 85 and 86: THE BRITISH SMUT FUNGI 83 Tilletia
Page 87 and 88: THE BRITISH SMUT FUNGI 85 bunt ball
Page 89 and 90: THE BEITISH SMUT FUNGI 87 globose t
Page 91 and 92: THE BRITISH SMUT FUNGI 89 FIG. 13.
Page 93 and 94: FIG. 15. Spore geimination in Taboi
Page 95 and 96: FIG. 17. Spore germination in Urocy
Page 97 and 98: THE BRITISH SMUT FUNGI 95 separate
Page 99 and 100: THE BRITISH SMUT FUNGI 97 8ori in t
Page 101 and 102:
THE BRITISH SMUT FUNGI 99 Urocystis
Page 103 and 104:
30390 THE BRITISH SMUT FUNGI 101 pr
Page 105 and 106:
FIG. 20. Spore geimination in Entyl
Page 107 and 108:
THE BRITISH SMUT FUNGI 105 Sori in
Page 109 and 110:
On Ranunculus ficariae and B. scler
Page 111 and 112:
THE BRITISH SMUT FUNGI 109 Infectio
Page 113 and 114:
THE BKITISH SMUT FUNGI 111 [Sporidi
Page 115 and 116:
THE BRITISH SMUT FUNGI 113 Ustilago
Page 117 and 118:
REFEEENCES 115 BBETT, M. A. (1940).
Page 119 and 120:
REFERENCES 117 ^ DniON WESTON, W. A
Page 121 and 122:
REFERENCES 119 GRIFFITHS, MAEIOK A.
Page 123 and 124:
REFERENCES 121 HtjTTiG, W. (1933).
Page 125 and 126:
REFEBENCES 123 LiMBOtruN, E. J. (19
Page 127 and 128:
REFERENCES 125 NOBLE, E. J. (1934).
Page 129 and 130:
REFERENCES 127 RoDENHiSEE, H. A., &
Page 131 and 132:
BEFERENCES 129 STAKMAK, E. C, XCEEN
Page 133 and 134:
EEFEEENCES 131 WAXTBE, J. M. (1934)
Page 135 and 136:
INDEX to generic and specific names
Page 137 and 138:
Muscari Ustilago vaillantii, 59 Myo
Page 139 and 140:
Ustilago ficuum Reich., 113 —flps
Page 141 and 142:
2i}:y0 ANDHRA PRADESH AGRICULTURAL
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