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Effects of root residues on growth ofPinus radiata seedlings and a mycorrhizal fungus
Author(s) -
CHUCHOU MYRA
Publication year - 1978
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1978.tb02650.x
Subject(s) - pinus radiata , radiata , biology , fungus , wilting , botany , nutrient , bark (sound) , vigna , horticulture , ecology
SUMMARY The height of Pinus radiata Don seedlings grown on soils incorporating different proportions of root tissues (25 and 50%) was shown to be reduced by 20–80%. Seedlings watered with aqueous extracts from soil/root mixtures also showed a significant reduction in growth. This growth‐retarding effect was partially overcome by the addition of nutrients or by soil sterilisation. It is postulated that growth retardation was caused not only by nutrient deficiency resulting from the addition of organic matter with a high C/N ratio, but also by phytotoxic substances present in the root tissue. The effect of water extracts of roots from old P. radiata trees on the growth of young P. radiata seedlings and on a mycorrhizal fungus ( Rhizopogon sp.) under aseptic conditions was also studied. Extracts from the inner bark of roots caused complete growth inhibition of the mycorrhizal fungus as well as root necrosis and wilting of P. radiata seedlings. A water‐soluble substance or substances, toxic both to the roots of P. radiata and to its mycorrhizal fungus, is postulated as the causal agent.