No abstract

Pleurotus species are said to be nematophagous because they paralyze and consume some bacterial-feeding nematodes. It has never been clear whether that means all nematodes. Here we tested thirteen bacterial-feeding nematode species: seven of family Rhabditidae, three of Cephalobidae (one with three populations), two of Panagrolaimidae, and one of Diplogastridae. Nematodes interacted on water agar with toxin-producing isolates of Pleurotus pulmonarius (Fr.) Quél. and Pleurotus ostreatus (Jacq.) P. Kumm. Of the thirteen species, nine were susceptible to P. pulmonarius (all individuals were paralyzed) but four (four populations of two cephalobid species, one rhabditid, and one panagrolaimid) survived exposure to P. pulmonarius. The resistant four species not only survived but multiplied their numbers by consuming P. pulmonarius. A similar trend was observed with nematodes interacting with P. ostreatus; however, six species were resistant to P. ostreatus. Interestingly, four of these six species were susceptible to P. pulmonarius, and interactions overall were differential. Pleurotus species are nematophagous toward some nematodes but are also consumed by others in three of the four families assayed. Species-specific interactions point to the need for studies of the host ranges of both “nematophagous” fungi and “fungivorous” nematodes, especially if they are to be used for biological control.

No abstract

Micropropagation is an alternative method for producing pathogenic contamination-free shallots seedlings. The aim of this research was to determine the optimum balance of auxin-cytokinin and sucrose concentration in stimulating the plantlet regeneration on shallot. The research was conducted from March to August 2019. In this study, the auxin and cytokinin treatment (1-5 ppm) were used in the format of a randomized complete block design in three replications. The basal plate containing a shoot bud was excised from healthy bulb and used as planting material. The explants had been through a sterilization process and was cultured aseptically in medium containing each treatment. Culture medium contained 7 g.L -1 agar powder and were adjusted at pH 5.8 before autoclaving. The multiple shootlet (10 weeks of cultured) were then subcultured for bulblet formation in MS medium supplemeted with BAP dan succrose (3-9%). The basal plate containing a shoot bud was excised from healthy bulb and used as planting material. The explants had been through a sterilization process and was cultured aseptically in medium containing each treatment. Culture medium contained 7 g L -1 agar powder and were adjusted at pH 5.8 before autoclaving. The results showed that the use of ½ MS media could increase the efficiency of using nutrient solution of tissue culture media. Micro shoot formation can be initiated on ½ MS medium with the addition of 1 ppm BAP (1.36 shoots / explants). This media also produced the best response for the number of micro roots (5.63 roots / explants), and the number of micro leaves (3.91 leaves). However, the difference in composition of nutrient in culture media was not able to accelerate the time of growth of shoots, roots and leaves. Further subculture in ½ strength of MS medium containing of BAP and sucrose 6% increased shoot, root and bulblet formation (13.3 shoots, 41.3 roots and 10.7 bulblets).