Control by arbuscular endomycorrhizae of Pratylenchus brachyurus in pineapple microplants Jean-Philippe Guillemin, Silvio Gianinazzi, Vivienne Gianinazzi-Pearson and Jean Marchal Guillemin, J.P. Gianinazzi, S. Gianinazzi-Pearson, V.' and Marchal, J. 2 1994. Control by arbuscular endomycorrhizae of Pratylenchus brachyurus in pineapple microplants. Agricultural Science in Finland 3: 253-262. (' Laboratoire de Phytoparasitologie, INRA-CNRS, Station de Génétique et d'Amélioration des Plantes, INRA, BV 1540, Dijon Cedex, France, and 2 Laboratoire de Physiologic et Biochimie, CIRAD, FLHOR, Avenue du Vai de Montferrant, BP 5035, 34032 Montpellier Cedex 01, France.) Pratylenchus brachyurus (Godfrey) Filip & Schurr-Steekh. has been reported in association with pineapple roots and is considered as an important pathogen on pineapple. Microplants of Queen Tahiti, Smooth Cayenne and Spanish varieties were inoculated with Glomus sp. (LPA2I) and/or P. brachyurus at transplanting from axenic conditions or one month later. The presence of the nematode did not affect shoot growth of endomycorrhizal plants. Late P. brachyurus inoculation did not influence growth of nonmycorrhizal plants while early pathogen application caused reductions in nonmycorrhizal plant growth. Nematode number per g of root was significantly decreased for endomycorrhizal plants when pathogen was intro- duced at outplanting or one month later. Nematode inoculation affected endomyc- orrhizal colonization estimated by non vital staining for the Queen Tahiti and Spanish varieties but did not alter development of metabolically active arbuscules in roots of the three varieties. P concentration of endomycorrhizal shoots was higher for all treatments and P. brachyurus tended to decrease mineral concentra- tion of nonmycorrhizal plants with early nematode application. Key words: Ananas comosus, endomycorrhizal infection, v/froplant, pathogen nem- atode, interactions, integrated control Introduction Arbuscular endomycorrhizal fungi (AMF) and soilborne pathogens occur together in the rhizo- sphere around plant roots. Arbuscular endomyc- orrhizae can positively influence plant develop- ment by improving mineral nutrition, water up- take, hormone production, resistance to root path- ogen or tolerance to pesticides (Gianinazzi et al. 1982). Guillemin et al. (1991) have shown the benefits to the growth of pineapple microplants of inoculation with endomycorrhizal fungi. Nematodes are considered an important factor in reducing pineapple production. Pratylenchus brachyurus (Godfrey) Filip & Schurr-Steekh. causes widespread damage in pineapple planta- tions, particularly in the Ivory Coast. It was de- scribed for the first time in pineapple roots by Godfrey (1929) in Hawaii. This nematode pene- trates the elongation zone of roots and develops in the cortical tissue and vascular cylinder (Guérout 1975). Secondary roots can then be destroyed by nematode infestation giving a root system that is essentially composed of primary 253 Agricultural Science in Finland 3 (1994) https://www.c-info.fi/en/info/?token=zKBMAAPs3i8-5CLt.ajxvdel1jXd5-zwQdWVEkA.BHSHK-Mv_jV_rIhM8VYgNjNIlNPpM5emCUZfYvZ4cRNcpRyfxKbqvvKHNbS7W5XbM0e6Y9bhoRQ0ytUhveXRQeN8P73CGilbkitUqD9KZer1JXQu49VHrdHl7pJUzDmQnJM-0hJhvkyOez3En7eEBidk3Rl_WjoFK34b-CfmyGSIXwjms4ZPhE1zjJo8ct0Ypa7WXS81bYo6oiBrro_fopT2inqDxGR7SgxfRZzLpCtSa0rFqNvngxguOAA5mpqJfudh-hcejuIYzUj0L4Hu1XYN39d9QTvOZfxnZU1krpbNf_RrCmw2wpWuKkx9KNbMjjPYXTKNW_3t7T8d1ER5d9gHUrvggrnE826GmcY-kw roots (Caswell et al. 1990). This endopathogen also modifies vegetative plant growth, with re- ductions in leaf area, and causes a delay in shoot development (Lacoeuilhe and Guérout 1976, Keetch 1982). Decreases in fruit yield can be in the region of 30 to 35% and the number of suck- ers may be reduced to 80% (Lacoeuilhe and Guérout 1976,Keetch 1982). P brachyurus has a high impact in the Ivory Coast (Guérout 1975), because pineapple is often grown in soil with a pH adapted to nematode proliferation (pH 5 to 5.5) (Sarah 1991). The potential of AMF to alleviate nematode- induced plant stress has been previously investi- gated in different plant species but variable host- plant responses to pathogen-endomycorrhiza in- teractions have been reported (e.g. Bagyaraj et al. 1979, Kellam and Schenck 1980, Cason et al. 1983, Elliot et al. 1984, Cooper and Grandi- son 1986, Smith 1987. Ingham 1988, Thomas et al. 1989). In the present work, we have tested interactive effects of AMF and P.brachyurus on plant growth, endomycorrhizal infection devel- opment and root-colonising nematode populations of micropropagated pineapple. Material and methods Three micropropagated pineapple varieties (Anan- as comosus (L.) Merr., Queen Tahiti, Smooth Cay- enne (clone CYO) and Spanish varieties) were tested. Plants were raised in a growth chamber under simulated tropical conditions (300pE s ' nr2 , 29-25°C, I2h day and 70%-90% relative humidity) in a y-irradiated (lOkGy) acid soil (pH 5.0). Pineapple microplants were inoculated with root fragments of Tephrosia ehlenbergiana infect- ed with an isolate of Glomus sp. (LPA2I) in trays containing a soihgravel (1:1, v:v) mix during a four-week acclimatization period (M) (Guille- min et al. 1991) or when one month-old weaned microplants were transplanted individually to pots (l+M). Each pot contained 400 g of the soihgravel mix and was watered daily with distilled water and weekly with 2x20 ml of Hoagland n°2 solu- tion (Hoagland and Arnon 1950) without phos- phate. Inoculation of Pratylenchus brachyurus was performed with about 100 nematodes per micro- plant at outplanting from axenic conditions (Nem- atode) or one month later at the end of the wean- ing period (Nematode+l). After 3 months in pots, several growth param- eters were evaluated: leaf area (cm 2), shoot and root fresh mass (g) and shoot dry mass (g) and the N, P, K, Ca and Mg concentrations of shoots determined (Warner and Jones 1967, Comité In- ter Instituts pour le diagnostic foliaire 1968, 1972). Endomycorrhiza development was estimated mi- croscopically by the method ofTrouvelot et al. (1986) after clearing roots and staining fungal tissue with trypan blue (Philipps and Hayman 1970), or for succinate dehydrogenase (SDH) (Smith and Gianinazzi-Pearson 1990) or alka- line phosphatase (ALP) (Tisserant et al. 1993) activities. Arbuscule frequency (A%) was also estimated and the proportion of living and func- tional arbuscules calculated as mentioned below: P. brachyurus in roots was extracted using the non-destructive procedure described by Sarah (1991). All treatments were tested in the same experi- ment for Smooth Cayenne and Spanish varieties however two experiments were done for Queen Tahiti variety. Each treatment consisted of 5 rep- A % after staining of SDH activity Proportion of living arbuscules = A % after staining with trypan blue A % after staining ofALP activity Proportion of functional arbuscules = A % after staining with trypan blue 254 Agricultural Science in Finland 3 (1994) licates and statistical analysis of data was per- formed using Newman-Keuls test following ANOVA. Results Both early (M) and late (I+M) inoculation with the AMF significantly increased the growth of plants compared with nonmycorrhizal controls whether they were infested or not with P. brachy- urus (Tables 1 and 4). Endomycorrhiza inoculation at trans- planting from axenic conditions With the single exception of Queen Tahiti variety root growth, both shoot and root growth of non- mycorrhizal microplants were significantly re- duced when nematodes were introduced at the beginning of the acclimatization period. However, shoot growth of the three pineapple varieties was not significantly modified by nematode infesta- tion in plants inoculated with the Glomus sp. at outplanting from axenic conditions (Table 1). Growth reductions due to the nematode were very limited and only occurred for leaf area (Spanish variety) and roots (Smooth Cayenne and Spanish varieties). Nematode number per g. of root was signifi- cantly lower in endomycorrhizal than nonmycor- rhizal roots for all three pineapple varieties (Ta- ble 1). Timing of P. brachyurus inoculation did not affect nematode numbers developing in the Queen Tahiti and Smooth Cayenne varieties, but later inoculation did reduce pathogen infestation in the Spanish variety (Table 1). Nematode infestation caused a reduction in P uptake by nonmycorrhizal plants, particularly for the Smooth Cayenne and Spanish varieties, but not in endomycorrhizal plants (Table 2). For the Spanish variety, N, Ca and Mg concentrations of nonmycorrhizal plants were also decreased by nematode infestation at transplanting. However, in endomycorrhizal plants P, Ca and Mg concen- trations in shoots of the three varieties inoculated with the nematodes were comparable to those of endomycorrhizal plants growing in the absence of nematodes (Table 2). Nematode application at outplanting signifi- cantly reduced arbuscule frequency (A%) for the Queen Tahiti and Spanish varieties after trypan blue staining (Table 3) but this reduction disap- peared with pathogen inoculation one month lat- er. This showed that it was of greatest benefit to establish endomycorrhizal colonization as soon as possible. Reduction of A% was also observed after staining for SDH and ALP activities in the Queen Tahiti variety (Table 3). The proportion of living and functional arbuscules was not altered by nematode infestation (Table 3). Endomycorrhizal inoculation at outplanting to pots Growth of endomycorrhizal plants was signifi- cantly greater than of nonmycorrhizal plants (Ta- ble 4). Inoculation with P. brachyurus at out- planting reduced the growth of nonmycorrhizal but not endomycorrhizal plants (Table 4). The nematode population was reduced in en- domycorrhizal plants with both timings of the pathogen application for the Queen Tahiti variety (Table 4) but this reduction was observed for the Smooth Cayenne and Spanish varieties only when nematodes and endomycorrhizae were inoculated simultaneously. Endomycorrhiza development af- ter nematode application did not influence nema- tode infestation of roots of the Smooth Cayenne and Spanish varieties. Timing of pathogen appli- cation influenced its presence in the roots of the Spanish variety; indeed the population was greater when the pathogen was introduced before inocu- lation with the AMF. Nematodes negatively affected P uptake by non- mycorrhizal but not endomycorrhizal plants (Ta- ble 5). Endomycorrhiza formation enhanced Ca and Mg contents of the Queen Tahiti and Spanish varieties and N concentration for the Spanish va- riety. K contents were higher for the nonmycor- rhizal plants. P. brachyurus application at outplanting sig- 255 Agricultural Science in Finland 3 (1994) Table 1; Leaf area (LA), shoot (SFM) and root (RFM) fresh mass, shoot dry mass (SDM) and number of nematodes per g. of roots (Nem root) of nonmycorrhizal (NM) and endomycorrhizal pineapple at transplanting from axenic conditions (M): nematode uninoculated (Control), inoculated (Nematode) and inoculated one month later (Nematode + 1). A - Queen Tahiti variety LA (cm2 ) SFM (g) RFM (g) SDM (g) Nem. root Control NM 186,9 b 15.26b 1.76b 1.54b 0c M 460.7a 36.01a 4,00 a 3.70a 0c Nematode NM 100.5c 7.35c 1.25b 0.91b 396 a M 353.7ab 27.31ab 3.12a 3.16a 232 b Nematode+l NM 209.0b 13.58b 1.71b 1.51b 330 a M 444.4a 34.16a 3.96a 3.58a 250 b B - Smooth Cayenne variety LA (cm2 ) SFM (g) RFM (g) SDM (g) Nem. root Control NM 299.8c 23.35c 2.63c 2.08b 0c M 640.9a 54.87a 5.48a 5.02a 0c Nematode NM 178.6d 13.82d 1.64d 1.39c 456 a M 540.6ab 42.86ab 3.44b 4.58a 267 b Nematode+l NM 232.7cd 19.75c 2.11c 2.09b 418 a M 547.5ab 48.38a 4.06b 4.64a 212 b C - Spanish variety LA (cm 2 ) SFM (g) RFM (g) SDM (g) Nem, root Control NM 313.2c 21.70b 2.05c 2.25c Od M 537.1a 38.48a 3.97a 3.91a Od Nematode NM 96.4d 5.72c 0.75d 0.74d 350 a M 476.9b 34.47a 2.77b 3.40ab 157 b Nematode+l NM 263.1c 19.57b 2.26c 1.97c 180 b M 543.6a 39.83a 3.40a 4.04a 46c Values in a column followed by different letters are significantly different (p<0.05) nificantly reduced arbuscule frequency (A%) de- termined after trypan blue staining in the Queen Tahiti and Spanish varieties (Table 3). A% evalu- ated by SDH and ALP activities was negatively affected by nematodes for the Queen Tahiti vari- ety. However, the proportion of living and func- tional arbuscules was not modified by P. brachy- urus for the three pineapple varieties (Table 3). Discussion Although P. brachyurus reduced the growth of nonmycorrhizal plants in all three pineapple va- rieties, in those colonized by AMF growth was not significantly affected. Precolonization of roots by AMF can therefore reduce the harmful effects of nematodes on plant growth. Simultaneous sym- biont and pathogen inoculation at transplanting to pots did not affect the growth of endomycor- rhizal pineapple. However, simultaneous inocu- lation of the AMF and nematodes at outplanting from axenic conditions slightly reduced growth of endomycorrhizal plants of the Queen Tahiti and Smooth Cayenne varieties. Both micro-or- ganisms can be an important photosynthate sink for very young micropropagated plantlets. Effects of the nematode on young microplants of pineap- ple during the acclimatization period are not irre- versible; indeed, late endomycorrhizal coloniza- 1256 Agricultural Science in Finland 3 (1994) Table 2: Mineral concentration (% of dry mass) of shoots of nonmycorrhizal (NM) and endomycorrhizal pineapple at outplanting from axenic conditions (M): nematode uninoculated (Control), inoculated (Nematode) and inoculated one month later (Nematode + I). A - Queen Tahiti variety N P K Ca Mg Control NM 2.040.08 4.600.81 0.29 M 1.700.18 3.590.96 0.37 Nematode NM 1.650.08 3.640.82 0.28 M 1.870.15 3.771.00 0.37 Nematode+l NM 1.830.05 4.010.87 0.28 M 1.770.18 3.491.04 0.37 B - Smooth Cayenne variety N P K Ca Mg Control NM 2.030.13 4.461.05 0.35 M 1.990.13 4.071.17 0.34 Nematode NM 1.930.07 4.521.08 0.35 M 1,81 0.143.54 1.090.32 Nematode+l NM 2.090.09 4.901.11 0.30 M 1.760.14 3.621.22 0.34 C - Spanish variety N P K Ca Mg Control NM 1.880.13 4.130.75 0.26 M 1.630.12 3.300.82 0.28 Nematode NM 1.410.04 3.670.60 0.19 M 1.670.14 3.060.95 0.30 Nematode+l NM 1.820.09 4.060.89 0.26 M 1.640.14 3.010.90 0.30 tion at transplanting to pots can compensate growth reductions of plants inoculated with nem- atodes at outplanting from axenic conditions. Mi- cropropagated plantlets could tolerate better the nematode inoculation at outplanting from axenic conditions followed one month later by endomy- corrhizal inoculation than both symbiotic and path- ogen inoculations at the beginning of the accli- matization period. The application of nematodes at outplanting from axenic conditions without en- domycorrhizal inoculation significantly reduced plant growth but this effect was not observed when plants were infested by nematodes one month later. This supports previous observations that older plants can tolerate pathogen infestation better than younger plants (Cooper and Grandi- son 1986). Pathogen effects on endomycorrhizal coloni- zation estimated after non vital staining varied with the pineapple variety. When nematodes were applied at transplanting this significantly reduced arbuscule frequency (A%) in the Queen Tahiti and Spanish varieties. The ability of nematodes to reduce endomycorrhizal development has also been observed by several authors (e.g. O’ B annon and Nemec 1979, Elliot et al. 1984), and it has been suggested that nematodes could induce an unfavourable environment for infection by the fungal symbiont (Thomas et al. 1989). Although nematode infestation negatively influenced val- 257 Agricultural Science in Finland 3 (1994) Table 3: Arbuscular frequency observed after staining with trypan blue (TB), succinate dehydrogenase (SDH) or alkaline phosphatase activities and proportion of living (SDH/TB) and functional (ALP/TB) arbuscules of endomycor- rhizal pineapple roots at outplanting from axenic conditions (M) and at transplanting to pots (l+M): nematode uninocu- lated (Control), inoculated (Nematode) and inoculated one month later (Nematode+l). Frequency of arbuscules (A%) detected by staining for Total fungal SDH SDH/TB ALB ALB/TB tissue (TB) activity (%) activity (%) Queen Tahiti variety M Control 63a 24.5 a 0.39 a 16.4 a 0.26 a Nematode 46b 14.7 b 0.32 a 9.4 b 0.21 a Nematode+l 56ab 17.4 b 0.31 a 12.0 b 0.22 a I+M Control 65a 19,0 a 0.29 a 12.7 a 0.20 a Nematode 33b 12.7 b 0,38 a B.ob 0.24 a Nematode+l 38b 13,6 b 0.36 a 9.2 b 0.24 a Smooth Cayenne variety M Control 65a 20.3 a 0.31 a 15.8 a 0.24 a Nematode 50a 20.0 a 0.40 a 13.9 a 0.27 a Nematode+l 51a 17.5 a 0.34 a 14.0 a 0.27 a I+M Control 53a 13.8 a 0.26 a 11.0 a 0.21 a Nematode 60a 10.9 a o.lBa B.oa 0.13 a Nematode+l 68a 14.9 a 0.22 a 10.3 a 0.15 a Spanish variety M Control 50a 21.6 a 0.43 a 13.8 a 0.28 a Nematode 29b 16.5 a 0.56 a 10.2 a 0.35 a Nematode+l 38ab 18.6 a 0.49 a 10.0 a 0,27 a I+M Control 40a 18.6 a 0.46 a 12.2 a 0.30 a Nematode 31b 16.7 a 0.54 a 9.4 a 0.30 a Nematode+l 35ab 14.4 a 0.41 a 9.4 a 0.27 a Values for each combination of variety and inoculation treatments (nematode and endomycorrhizal fungus) followed by different letters are significantly different (p<0.05) ues for A% of Queen Tahiti variety estimated by SDH and ALP activities, P. bmchyurus did not affect the proportion of living and functional ar- buscules of the three pineapple varieties, and con- sequently did not influence the efficiency of the symbiosis for pineapple. This could partly ex- plain the lack of effect of P. bmchyurus on the growth of endomycorrhizal plants. Several reports have shown that endomycor- rhizal colonization decreases nematode popula- tions in root systems (e.g. Bagyaraj et al. 1979, Saleh and Sikora 1984), and Smith et al. (1986) showed that AMP can enhance plant tolerance to nematodes in field conditions. In this study, num- bers of nematodes were also significantly reduced in the roots of endomycorrhizal pineapple of the three varieties in comparison to nonmycorrhizal plants, whether nematodes were applied simulta- neously with or after the AMP. Reductions in nematode infection have been attributed to modi- fications in plant physiology caused by the sym- biotic fungi. AMP are able to ensure an adequate P nutrition in presence of nematodes and since P is considered as an important factor in plant tol- erance (Smith and Kaplan 1988), higher con- centrations of this element in endomycorrhizal tissues could have a direct action reducing nema- tode numbers in roots (MacGuidwin et al. 1985). Changes in root exudates may also alter root at- tractiveness for nematodes (MacGuidwin et al. 1985), or induce physical and chemical barriers to root penetration (Kellam and Schenck 1980). 258 Agricultural Science in Finland 3 (1994) Table 4: Leaf area (LA), shoot (SFM) and root (RFM) fresh mass, shoot dry mass (SDM) and number of nematodes per g. of roots (Nem root) of nonmycorrhizal (NM) and endomycorrhizal pineapple at transplanting to pot (l+M): nema- tode uninoculated (Control), inoculated (Nematode) and inoculated one month later (Nematode+l). A - Queen Tahiti variety LA (cm 2) SFM (g) RFM (g) SDM (g) Nem. root Control NM 312.4b 24.82b 2.52b 2.58b 0c I+M 452.9a 33.85a 3.19a 3.36a 0c Nematode NM 136.9c 10.95c 1.19c 1.13c 564 a I+M 389.5ab 31.62a 2.74ab 3.00a 300 b Nematode+l NM 176.7c 13.11c 1.26c 1.28c 465 a I+M 433.8a 35.26a 2.77ab 3.53a 304 b B - Smooth Cayenne variety LA (cm 2) SFM (g) RFM (g) SDM (g) Nem. root Control NM I+M Nematode NM I+M Nematode+l NM I+M 299.8b 471.7a 178.6c 362.3ab 232.7bc 485.1a 23.35b 2.63b 2.08b 34.65a 3.06a 3.07a 13.82c 1.64c 1.39c 31.24a 2.84a 3.65a 19.75b 2.11b 2.09b 35.47a 3.05a 3.85a Oc Oc 456a 389a 418a 293b C - Spanish variety LA (cm 2 ) SFM (g) RFM (g) SDM (g) Nem, root Control NM 313.2b 21.70b 2.05b 2.25b Od I+M 483.5a 33.45a 2.92a 3.23a Od Nematode NM 96.4c 5.72c 0.75c 0.74c 350 a I+M 465.0a 33.68a 2.29ab 3.40a 330 a Nematode+l NM 263.1b 19.57b 2.26ab 1.97b 180 b I+M 432.7a 31.29a 2.65a 2.85a 122 c Values in a column followed by different letters are significantly different (p<0.05) Endomycorrhizal colonization could also repre- sent a competition for photosynthates in roots (Smith 1987), and thus produce a less favourable environment for the nematodes (Kellam and Schenck 1980) or influence the quality of food reserves of nematodes (MacGuidwin et al. 1985). Endomycorrhizal plants have higher sugar con- tents, modified hormone balance and modifica- tions in the composition of amino acids (e.g in- creases in serine and phenylalanine which are nematicidal) (Suresh et al. 1985). Presence of a fungal symbiont in roots can affect the normal life cycle of nematodes (Cason et al. 1983) and reduce nematode size (Sitaramaiah and Sikora 1982). Other micro-organisms such as bacteria and fungi are also considered as antagonists to nema- todes (Cayrol et al. 1992), and the combination of AMF with one or several antagonists could produce a more beneficial synergistic action on plant protection and growth. Fallow could be also used to combat nematode populations in soil (Stir- ling and Nikulin 1993), but this approach risks decreasing endomycorrhizal potential and reduc- ing soil fertility (Sarah 1987) unless inoculation with efficient AMF after fallow is ensured. The control of nematodes in pineapple, which avoids excess use of nematicides, clearly requires an in- tegrated approach. The results reported here sug- gest that endomycorrhizae, which are not affect- 259 Agricultural Science in Finland 3 (1994) Table 5: Mineral concentration (% of dry mass) of shoots of nonmycorrhizal (NM) and endomycorrhizal pineapple at transplanting to pots (l+M): nematode uninoculated (Control), inoculated (Nematode) and inoculated one month later (Nematode+l). A - Queen Tahiti variety N P K Ca Mg Control NM 1.72 0.10 3.83 0.83 0.33 I+M 1.76 0.17 3.74 0.79 0,33 Nematode NM 1.83 0.05 4.60 0.67 0.24 I+M 1.95 0.13 3.91 0.88 0.34 Nematode+l NM 2.22 0.08 5.25 0.74 0.27 I+M 1.81 0.12 3.42 0.91 0.32 B - Smooth Cayenne variety N P K Ca Mg Control NM 2.03 0,13 4.46 1.05 0.35 I+M 2.26 0,16 4,46 1.18 0.33 Nematode NM 1.93 0.07 4.52 1.08 0.35 I+M 1.70 0.16 3.38 1.03 0.33 Nematode+l NM 2.09 0.09 4.90 1.11 0.30 I+M 1.85 0.16 3.68 1.13 0.35 C - Spanish variety N P K Ca Mg Control NM 1.88 0.13 4.13 0.75 0.26 I+M 1.97 0.16 4.01 0.83 0.27 Nematode NM 1.41 0.04 3.67 0.60 0.19 I+M 1.74 0.13 3.18 0.83 0.26 Nematode+l NM 1.82 0.09 4.06 0.89 0.26 I+M 1.98 0.14 3.98 0.91 0.27 ed by nematicides (Habte and Manjunath 1988), could be a valuable component in a scheme of integrated protection against nematodes. Acknowledgements. The authors thank Vitropic S.A. (Montpellier, France) for supplying the micropropagated plant material and Dr J.L. Sarah (CIRAD, FHLOR, Montpellier, France) for supplying P. brachyurus. References Bagyaraj, D.J., Manjunath, A. & Reddy, D.D.R. 1979. Interaction of vesicular-arbuscular mycorrhiza fungi with root-knot nematodes in tomato. Plant and Soil 51: 397-403. Cason, K.M.T., Hussey, R.S. & Roncadori, R.W. 1983. Interaction of vesicular-arbuscular mycorrhizal fungi and phosphorus with Meloidogyne incognita on toma- to, Journal of Nematology 15: 410-417. Caswell, E.P., Sarah, J.L. & Apt, W.J. 1990. Nematode parasites of pineapple. In: Luc, M., Sikora, R.A. & Bridge, J. (eds.). Plant parasitic nematodes in subtropi- cal and tropical agriculture, CAB International, p. 519-537. Cayrol, J.C., Djian-Caporalion, C. & Panchaud-Mat- tei, E. 1992. La lutte biologique contre les nématodes phytoparasites. Courrier de la Cellule Environnement de ITNRA 17: 31-44. Comité Inter Instituts pour le diagnostic foliaire 1968. Méthode de référence pour la détermination des élé- ments minéraux dans les végétaux. Coll. Eur. Méd. sur 260 Agricultural Science In Finland 3 (1994) le controle de I'alimentation des Plantes cultivées, Séville. p. 12-20. 1972. Méthode de référence pour la détermination des éléments minéraux dans les végétaux. Coll. Eur. Méd. sur le controle de I'alimentation des Plantes cultivées, Budapest, p. 144-150. Cooper, K.M. & Grandison, G.S. 1986. Interaction of vesicular-arbuscular mycorrhizal fungi and root-knot nematode on cultivars of tomato and white clover sus- ceptible to Meloidogyne hapta. Annals ofApplied Bi- ology 108: 555-565. Elliot, A.P., Bird, G.W. & Safir, G.R. 1984. Joint influ- ence of Pratylenchus penetrans (nematoda) and Glomus fasciculatum (phytomyceta) on the ontogeny of Phase- olus vulgaris. Nematropica 14: 111-119. Gianinazzi, S., Gianinazzi-Pearson, V. & Trouvelot, A. 1982. Les Mycorhizes, Partie Intégrante de la Plante: Biologie et Perspective d'Utilisation. 397 p. INRA- Presse, Paris, France. Godfrey, G.H. 1929. A destructive root disease of pine- apple and other plants due to Tylenchus brachyurus. Phytopathology 19: 611-629. Guérout, R. 1975. Nematodes of pineapple: a review. Pest Articles & News Summaries 21: 123-140. Guillemin, J.P., Gianinazzi, S. & Gianinazzi-Pearson, V. 1991. L'endomycorhization de vitroplants d 'Ananas co- mosus: mise en évidence d’un effet mycorhizien. Fruits 46: 355-358. Habte, M. & Manjunath, A. 1988. Influence of phen- amiphos on the vesicular-arbuscular mycorrhizal sym- biosis in Leucaena leucocephala. Biology and Fertili- ty of Soils 5: 313-316. Hoagland, D.R. & Arnon, D.I. 1950. The water-culture method for growing plants without soil. California Ag- ricultural Experiment Station Circular 347: 1-32. Ingham, R.E. 1988. Interactions between nematodes and vesicular-arbuscular mycorrhizae. Agriculture, Ecosys- tems and Environment 24: 169-182. Keetch, D.P. 1982. Nematode pests of pineapple. In: Keetch, D.P. & Heyns, J. (eds.). Nematology in South Africa. Department of Agriculture and Fisheries, Pre- toria. p. 19-29. Kellam, M.K. & Schenck, N.C. 1980. Interactions be- tween a vesicular-arbuscular mycorrhizal fungus and root-knot nematode on soybean. Phytopathology 70: 293-296. Lacoeuilhe, J.J. & Guérout, R. 1976. Action du néma- tode Pratylenchus brachyurus sur la croissance, la nu- trition et les rendements de I’ananas ’Cayenne lisse’. Influence de la localisation de la fumure. Fruits 31: 147-156. MacGuidwin, A.E., Bird, G.W. & Safir, G.R. 1985. In- fluence of Glomus fasciculatum on Meloidogyne hap- la infecting Allium cepa. Journal of Nematology 17: 389-395. O'Bannon, J.H. & Nemec, S. 1979. The response of Cit- rus limon to a symbiot, Glomus etunicatus , and a path- ogen, Radopholus similis. Journal of Nematology 11: 270-275. Philipps, J.M. & Hayman, D.S. 1970. Improved proce- dures for clearing roots and staining parasitic and ve- sicular-arbuscular mycorrhizal fungi for rapid assess- ment of infection. Transactions of the British Myco- logical Society 55: 158-161. Saleh, H. & Sikora, R.A. 1984. Relationship between Glomus fasciculatum root colonization of cotton and its effect on Meloidogyne incognita. Nematologica 30: 230-237. Sarah, J.L. 1987. Utilisation d'une jachére travaillée pour lutter centre les nématodes parasites de I'ananas. Fruits 42: 357-360. - 1991. Effect of soil pH on development of Pratylen- chus brachyurus populations in pineapple roots. Nema- tropica 21: 211-216. Sitaramaiah, K. & Sikora, R.A. 1982. Effect of the my- corrhizal fungus Glomus fasciculatus on the host-par- asite relationship of Rotylenchulus reniformis in toma- to. Nematologica 28: 412-419. Smith, G.S. 1987. Interactions of nematodes with mycor- rhizal fungi. In: Veech, J.A. & Dickson, D.W. (eds.). Vistas on Nematology, Society of Nematologists, Hy- attsville, MD. p. 292-300. - & Kaplan, D.T. 1988. Influence of mycorrhizal fun- gus, phosphorus, and burrowing nematode interactions on growth of rough lemon citrus seedlings. Journal of Nematology 20; 539-544. -, Roncadori, R.W, & Hussey, R.S. 1986. Interaction of endomycorrhizal fungi, superphosphate, and Meloido- gyne incognita on cotton in microplot and field stud- ies. Journal of Nematology 18: 208-216. Smith, S.E. & Gianinazzi-Pearson, V. 1990. Phosphate uptake and vesicular-arbuscular activity in mycorrhiz- al Allium cepa L.: effect of photon irradiance and phos- phate nutrition. Australian Journal of Plant Physiology 17: 177-188. Stirling, G.R. & Nikulin, A. 1993. Population dynamics of plant parasitic nematodes in Queenland pineapple fields and the effects of these nematodes on pineapple production. Australian Journal of Experimental Agri- culture 33: 197-206. Suresh, C.K., Bagyaraj, D.J. & Reddy, D.D.R. 1985. Effect of vesicular-arbuscular mycorrhiza on survival, penetration and development of root-knot nematode in tomato. Plant and Soil 87: 305-308. Thomas, G.V., Sundararaju, P., Ali, S.S. & Ghai, S.K. 1989. Individual and interactive effects of VA mycor- rhizal fungi and root-knot nematode, Meloidogyne in- cognita, on cardamom. Tropical Agriculture 66: 21-24. Tisserant, 8., Gianinazzi-Pearson, V, Gianinazzi, S. & Gollote, A. 1993. In planta histochemical staining of fungal alkaline phosphatase activity for analysis of ef- ficient arbuscular endomycorrhizal infections. Myco- logical Research 97: 245-250. Trouvelot, A., Rough, J. & Gianinazzi-Pearson, V. 1986. Mesure du taux de mycorhization VA d'un systéme radiculaire. Recherche de méthodes d'estimation ayant une signification fonctionnelle. In: Gianinazzi-Pearson, 261 Agricultural Science in Finland 3 (1994) V. & Gianinazzi, S. (eds.). Mycorrhizae: Physiology and Genetics. INRA-Press, Paris, p. 217-221. cal chemistry, Vol. I. Mediad Inc., New York. p. 145 148. Warner, M.H. & Jones, J.B. 1967. Determination of to- tal tissue using a Technicon Kjeldahl Nitrogen appara- tus. Technicon Symposia 1966, Automation in analyti- Manuscript received February 1994 SELOSTUS Arbuskelimykorritsasienten käyttö Pratylenchus hrachyurus -ankeroisen torjunnassa mikrolisätyllä ananaksella Jean-Philippe Guillemin Silvio Gianinazzi 1, Vivienne Gianinazzi-Pearson' ja Jean Marchal2 1 Laboratoire de Pytoparasitologie, INRA-CNRS, Station de Génétique et d’Ameloration des Plantes, INRA, Dijon, Ranska ja 2 Laboratoire de Physiologic et Biochimie, CIRAD, FLHOR, Montpellier, Ranska Ananaksen juuristosta tavattua ankeroista Pratylenchus hrachyrus pidetään merkittävänä taudinaiheuttajana ana- nasviljelyksillä. Mikrolisättyihin ananaslajikkeisiin ‘Queen Tahiti’, ‘Smooth Cayenne’ ja ‘Spanish’ siirrostettiin Glo- mM-s-mykorritsasientä ja/tai ne tartutettiin P. hrachyrus -ankeroisella. Siirrostus ja tartutus suoritettiin välittömäs- ti ananaksen in vitro -vaiheen jälkeen tai kuukautta myö- hemmin. Ankeroinen ei haitannut mykorritsallisten tai- mien kasvua. Ankeroisen aikainen tartutus heikensi my- korritsattomien taimien kasvua mutta myöhäinen tartutus ei. Mykorritsan ansiosta ankeroisten lukumäärä/juurigram- ma väheni ankeroistartutuksen ajankohdasta riippumatta Ankeroiset vähensivät merkittävästi mykorritsasienen ko- konaisinfektiota lajikkeissa ‘Queen Tahiti’ ja ‘Spanish' mutta eivät vaikuttaneet metabolisesti aktiivisten arbus- keleiden kehitykseen tutkittujen kolmen lajikkeen juuris- tossa. Mykorritsasiirrostus lisäsi kasvien versojen fosfori- pitoisuutta. Aikainen ankeroistartutus vähensi hiukan my- korritsattomien kasvien kivennäispitoisuuksia. 262 Agricultural Science in Finland 3 (1994)