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To produce virus-free plants, a simple and original protocol was established by combining several techniques: repeated shoot meristem excision before and during in vitro culture and thermotherapy applied to bulblets in vitro. Lily symptomless virus (LSV) is a major virus that decreases plant growth vigor and the quality of cut flowers, yet infected plants show no distinct symptoms. Stock bulbs of pollenless Asiatic hybrid lily (L. × elegans Thunb) lines (‘409’ and ‘599’) were used as explant. Shoot meristems were excised and micropropagated. Thermotherapy (42 days at 35 °C) was applied to in vitro growing bulblets and a second meristem cut was then made from heat-treated material. Leaf tissues from bulblets formed before or postheat treatments were analyzed either by enzyme-linked immunosorbent assay or by reverse transcriptase–polymerase chain reaction. Line ‘499’ produced LSV-free plants without heat treatment, but line ‘599’ produced LSV-free plants only after heat treatment. The virus-free lily bulblets grew vigorously in vitro and acclimatized promptly. It is suggested that thermotherapy given to in vitro growing bulblets effectively eliminated the virus and induced a fast and efficient micropropagation technique for virus-free mother plant stock.

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The promotion, at local level, of resource recycling chains, with low environmental impact and costs, appears of great interest for the production of green composts to replace peat in ornamental crops. In this work, two green composts, differing for the criterion of raw material selection for composting, were tested for the cultivation of two bedding plants in comparison with 100% peat based substrate. Leaf chlorophyll (SPAD index), biometric and growth parameters, and tissue mineral composition were measured to assess growing media-plant system performances. Both growing media and plants gave heterogeneous responses depending on substrate characteristics and plant requirements and/or tolerance to abiotic stress. Plant biomass was reduced by 63% (on average) in the most sensitive species due to the high Cl concentration detected in one of the two green composts; a similar trend was observed for SPAD index. The results support the shared idea that the selection of raw material is a strategy of primary importance in the composting process to obtain high quality green compost.

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