BY SHERIFF O. SANNI. Federal Department of Agricultureal Research, Moor Plantation, P.M.B. 5042, Ibadan, Nigeria. [Received i August 1975) SUMMARY

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1 New Phytol. (1976) 77, VESICULAR-ARBUSCULAR MYCORRHIZA IN SOME NIGERIAN SOILS AND THEIR EFFECT ON THE GROWTH OF COWPEA (VIGNA UNGUICULATA), TOMATO {LYCOPERSICON ESCULENTUM) AND MMZE {ZEA MAYS) BY SHERIFF O. SANNI Federal Department of Agricultureal Research, Moor Plantation, P.M.B. 5042, Ibadan, Nigeria [Received i August 1975) SUMMARY Spores of fungi forming vesicular-arbuscular mycorrhiza were collected from Ibadan, Iwo and Egbeda series at the experimental plots of Federal Department of Agricultural Research, Moor Plantation, Ibadan. These were used to inoculate cowpea, maize and tomato. The presence of vesicular-arbuscular mycorrhiza was detected in the roots of these plants after a few weeks of growth. Dry weights of roots and shoots, and total P and N were determined. There was a positive correlation between the presence of vesicular-arbuscular mycorrhiza and the airounts of P and N in the tissues. INTRODUCTION Improved growth of plants with VA mycorrhiza has been obtained in soil by many investigators (Baylis, 1959, 1967, 1969; Clark, 1969; Gerdemann, 1964, 1965; Holevas, 1966; Mosse, 1957). Some plants have been observed to exhibit enhanced phosphorus uptake when inoculated with endogonaceous spores forming VA mycorrhiza (Hayman and Mosse, 1971; Baylis, 1959; Gerdemann, 1965; Ross and Harper, 1970). Most of these results were obtained from spores collected in temperate regions. Old, Nicolson and Redhead (1973) described a new species of mycorrhizal endogonaceae from Nigeria with a distinctive spore wall. Also, Redhead (1974) described endotropbic mycorrhizas in Nigeria especially in relation to economic forest trees. This paper describes a collation of endogonaceous spores normally found around Ibadan and their effects on phosphorus absorption by cow pea, maize and tomoto. MATERIALS AND METHODS Soil samples were collected in plots under different fallows with Stylosanthes gracilis, Galopogonium mucunoides, and a secondary forest with only Teak [Tectonagrandis) stands./ Volumes of soil (30 x 30 x 15 cm) were transferred into polyethylene bags and wetsieved by methods described by Gerdemann (1955). The most useful spores were collected from loo-jim, 2oo-/im and 25o-/im sieves. Type I spores was used for maize, Type II for cowpea and Type III for tomato. T'he soil used contained 5.1 ppm available P, 0.680% N, and bad a ph of 7.4. The soil 667

2 668 SHERIFF O. SANNI was air-dried and passed through a 2-mm sieve and sterilized by autoclaving. Five-litre plastic buckets were filled with the sterile soil up to 5 cm from the top. Maize variety, Nigerian Composite C, Prima variety of cowpea and Harvester variety of tomato were used for the experiment. To inoculate the maize and cowpea, holes 4 cm diameter and 6 cm deep were excavated in the soil and suspension of spores (twenty spores per hole) were pipetted into the holes and covered lightly with soil before planting 3 cm above the spores at two seeds per bucket. To inoculate the tomato, 6-day-oId seedlings were transplanted to the sterile soil from an interrhediate soil. The roots were gently shaken in order to remove most of the soil adhering to them and lowered into holes excavated in the sterile soil. Fifty spores were then pipetted directly onto the roots and covered with soil. The treatments included the following; plants + spores, plants + spores+ Ca3(PO4)2, plants-fca3(po4)2 and control. Long Ashton solution, without P, was added to all treatments after i week of inoculation. Moisture lost was replaced with sterile distilled water. RESULTS Descriptions of the most typical spores used for the experiment are as follows. Type I. Bulbous reticulate, whitish cream, to greenish yellow. Most numerous in samples sieved in Moor Plantation. Spherical, about jum diameter. Occurring singly often with attachment which could be simple or swollen. Oil droplets which may be visible under high magnification may be present (Plate i, Nos i and 2). Found mainly in Egbeda soil series. Type II. Bulbous reticulate, golden yellow colour. Spherical ^m diameter. Similar to that described by Redhead (1974) isolated from Miango, Jos Plateau. Mostly occurring singly with or without attachment. Oil vacuoles or droplets clearly visible under immersion (Plate i. No. 3). This spore resembles Thaxter. Very numerous in Ibadan series in Moore Plantation. Type III. Spherical, brown to black colour, fiva. Attachment present which may be double or single. These spores are not so numerous as Types I and II; appearing singly or mixed with other spores. When Type I is in a majority in any one sample the white variety (Type I) may be scarce in that particular soil type. Probably similar to that described by Redhead (1974) (Plate i. No. 4; Plate 2, No. 5). Commonly found in Iwo series. From the description of spores above it is obvious that the commonest spore types in Ibadan are species belonging to the genus Gigas pora. According to classification by Gerdemann and Trappe (1974) Type I corresponded to G. gigantea, Type II to G. gilmorei and Type III to G. coralloidea. However, soils from Jos, Illorin and Samaru in part of Nigeria contained more Glomus mosseae and G. fasciculatus than Gigospora species commonly found in Ibadan area. Diagnosis of infection After some weeks of growth the shoots of the plants were cut off and roots and

$'S^Km^l VESICULAR-ARBUSCULAR MYCORRHIZA {facing page$

3 THE NEW PHYTOLOGIST, 77, 3 PLATE I i SHERRIFF O. 'S^Km^l VESICULAR-ARBUSCULAR MYCORRHIZA {facing page 668)

4 THE NEW PHYTOLOGIST, 77, 3 PLATE 2 EXPLANATION OF PLATES PLATE I No. I. Gigaspora gigantea spore sieved from Egbeda series showing bulbous septate attachment and hyphae emenating from the attachment to the spore. No. 2. G. gilmorei with oil droplet visible. Nos. 3 and 4. G. coralloidea showing spores with single or double attachment. PLATE 2 No. 5. Material from mycorhizal root system showing infected portion darkly stained and non-infected lighter portion; external mycelium bearing single azygospore could be seen. No. 6. Most probably to be G. gigantea but with spiral attachment, this spore was dark brown to black. SHERRIFF O. VESICULAR-ARBUSCULAR MYCORRHIZA

5 Vesicular-arhuscular mycorrhiza 669 shoots were shaken in clean water until they were freed of adhering soil. The roots were cut into I cm pieces, heated for 10 min in chloral hydrate, stained in 0.01 % Acid Fuschocin or Cotton Blue and examined under the microscope. All inoculated roots were found to be heavily infected with the endophyte. Vesicles, arbuscules and extramatrical hyphae were recognized in mycorrhizal roots. Chemical analyses of plant tissues Cowpea. The roots and shoots of the cowpea were analysed for total N and P after 80 days of growth (Table i). in both roots and shoots of inoculated plants was greater than P observed in the control treatment. More P was translocated to the shoots in Table i. Dry weights of shoots and roots of cowpea, total P and N in tissues in So-day-old seedlings Treatments Control Seeds + spores Seeds + Ca3(PO4)2 Seeds + spores + Ca3(PO4)2 I.I * Shoots ** 3-2** 6.8** II Roots Significantly different from control at 5%*, and 1%** level respectively. Table 2. Dry weights of shoots and roots, total P and N in tissues of maize in ^g-day-old seedlings Treatments Sand/gravel Sand/gravel + spores Soil + I2 + spores ** 30.55** Shoots * ** Roots * 6.15** 10.61** ** ** Significantly different from control at 5%*, and 1%** level respectively. mycorrhizal plants than the control, although this cannot be said to be significant. Treatments with an insoluble source of phosphate but without inoculation contained greater amounts of P in the plant tissues than the control. Phosphorus absorption was further enhanced from soil which contained insoluble Ca3(PO4)2 by inoculation with endogonaceous spores. in the shoots and roots were 6.8 mg and 3.2 mg in treatments with spores plus Ca3(PO4)2 compared to 3.2 mg and 2.0 mg in shoots and roots respectively in treatments with Ca3(PO4)2 alone. was much greater in treatments with either VA mycorrhiza, Ca3(PO4)2 or both than in control plants. Maize. In this experiment maize was planted in soil-gravel mixture which contained very low level of available P. Dry weights of shoots and roots, total P and N in these tissues were greater in mycorrhizal plants, but not significantly. In another set of experiments in which low-phosphate soil was used instead of sand-gravel mixture, dry weights and total P in tissues were significantly higher than control. Ca3(PO4)2 alone in the sand-gravel mixture was observed to enhance P absorption than treatments

6 670 SHERIFF O. SANNI inoculated with spores. In the latter, the level of infection by the endophyte was observed to be very low. Tomato. Mycorrhizal tomato roots showed more vigorous growth than control. The crop grew well in both treatments but plants with infected roots contained greater P and N than control; the total N could not be said to be significant (Table 3). Table 3. Dry weights of shoots and roots, total P and N in tissues of tomato in III -day-old seedlings Treatments Control Seedlings -1- spores Shoots * * Significantly diflferent from the control at 5%* level. Roots DISCUSSION From this investigation it would be seen that Gigospora species slightly differing in sizes from those described by Gerdemann and Trappe (1974) are very good inocula and produced profuse VA mycorrhizae in the plants used. In very low phosphate environment, simulated in this experiment by the use of sand-gravel mixture, inoculation with spores did not significantly affect phosphate absorption. Although available P seemed to be limiting to plant growth physical impedance to both lateral and longitudinal root extension might also be another limiting factor to plant growth in this treatment. In this investigation, however, the pattern of P translocation was of interest. In the control plants grown in highly P-deficient media greater amounts of P were observed in the roots than in the shoots; about 2: i ratio. But greater amounts of P were observed in the shoots when the growth media received either Ca3(PO4)2 or endogonaceous spores. Sanni (1973) observed similar phenomenon in wheat when inoculated with phosphatedissolving bacteria. The activity of the root-endomycorrhiza complex was greatly enhanced by the addition of C3(PO4)2 as observed in the three test plants. Similar observations have been made by Daft and Nicolson (1966) using bone meal, Murdoch, Jackobs and Gerdemann (1967) using apatite, and tricalcium phosphate; and Jackson, Franklin and Miller (1972) using rock phosphate as insoluble sources of phosphate. ACKNOWLEDGMENTS I highly appreciate the useful information passed on to me by my colleague, Dr B. A. Okusanya, in this investigation. BAYLIS, G. T. S. (1959). Effect of vesicular-arbuscular mycorrhizas on growth of Griselina littoralis (Cornaceae). New Phytol., 58, 274. BAYLIS, G. T. S. (1967). Experiments on the ecological significance of phycomycetous mycorrhizas. New Phytol., 66, 231.

$Vesicular-arbuscular mycorrhiza 671 CLARK, F. B. (1969). Endotrophic mycorrhizal ir\fection of tree seedlings with Endogone spores. Forest Set., IS, 134. DAFT, M. J. & NICOLSON, T. H. (1966).$

7 Vesicular-arbuscular mycorrhiza 671 CLARK, F. B. (1969). Endotrophic mycorrhizal ir\fection of tree seedlings with Endogone spores. Forest Set., IS, 134. DAFT, M. J. & NICOLSON, T. H. (1966). Effect of Endogone mycorrhiza on plant growth. New Phytol., 65, 243- GERDEMANN, J. W. (1955). Relation of a large soil-borne spore to phycomycetous mycorrhizal infections. Mycologia, 47, 619. GERDEMANN, J. W. (1964). The effect of mycorrhiza on the growth of maize. Mycologia, 56, 342. GERDEMANN, J. W. (1965). Vesicular-arbuscular mycorrhizae formed on maize and tulip-tree by Endogone fasciculata. Mycologia, 57, 562. GERDEMANN, J. W. & TRAPPE, J. M. (1974). The Endogonaceae in the Pacific Northwest. Mycologia memoir. No. 5- HAYMAN, D, S. & MOSSE, B. (1971). Plant growth responses to vesicular-arbuscular mycorrhiza. I. Growth of.emdo^one-inoculated plants in phosphate deficient soils. New Phytol., 70, 19. HoLEHAS, C. D. (1966). The effect of vesicular-arbuscular mycorrhiza on the uptake of soil phosphorus by strawberry {Fragaria sp. var. Cambridge Favourite), y. hort. Sci., 41, 57. JACKSON, N. E., FRANKLIN, R. E. & MILLER, R. H. (1972). Effects of VA mycorrhizae on growth and phosphorus content of three agronomic crops. Proc. Soil Sci. Soc. Am. 36, 62. MOSSE, B. (1957). Growth and chemical composition of mycorrhizal and non-mycorrhizal apples. Nature, Lond., 179, 922. MURDOCH, C. L., JACKOBS, J. A., & GERDEMANN, J. W. (1967). Utilization of phosphorus sources of different availability by mycorrhizal and non-mycorrhizal maize. Plant Soil, 27, 329. OLD, K. M., NICOLSON, T. H. & REDHEAD, J. F. (1973). A new species of mycorrhizal Endogone from Nigeria with distinctive spore wall. New Phytol., 72, 817. REDHEAD, J. F. (1974). Endotrophic mycorrhizas in Nigeria. Ph.D. thesis. Department of Forestry, University of Ibadan, Nigeria. Ross, J. P. & HARPER, J. A. (1970). Effect of Endogone mycorrhiza on soybean yields. Phytopathology, 60, SANNI, S. O. (1973). Occurrence and activity of phosphate-dissolving bacteria. Ph.D. thesis, Czechoslovak Academy of Science, Institute of Microbiology, Prague, pp. 70.

COMPONENTS OF VA MYCORRHIZAL INOCULUM AND THEIR EFFECTS ON GROWTH OF ONION

COMPONENTS OF VA MYCORRHIZAL INOCULUM AND THEIR EFFECTS ON GROWTH OF ONION New Phytol. (1981) 87, 3 5 5.161 355 OMPONENTS OF VA MYORRHIZAL INOULUM AND THEIR EFFETS ON GROWTH OF ONION BY A. MANJUNATH AND D. J. BAGYARAJ Depart?nent of Agricultural Microbiology, University of Agricultural