Physiological Response of Lily (Lilium sp.) Plants to Stress

E. T. IAKIMOVA1, V. M. KAPCHINA-TOTEVA2, S. M. BISTRICHANOV1, S. T. DENKOVA1 and I. I. IVANOVA1
1 AgroBioInstitute, Department Floriculture, Bg-1222 Negovan, Sofia, Bulgaria
2 University of Sofia, Faculty of Biology, BG-1421 Sofia, Bulgaria

Abstract

IAKIMOVA, E. T., V. M. KAPCHINA-TOTEVA, S. M. BISTRICHANOV, S. T. DENKOVA and I. I. IVANOVA, 2002. Physiological response of Lily (Lilium sp.) plants to stress. Bulg. J. Agric. Sci., 8: 499–506

These experiments were undertaken to elucidate what is the biochemical and physiological response of lily plants to viral and fungal infection and herbicide treatments.
Lily symptomless virus is the most spread virus on lily plant and nearly all of the production areas in our country are strongly infected. Also, a serious damage of lilies is caused by infection of Fusarium oxisporum f. sp. Lilii. The treatment with herbicides is an indispensable part of lily cultivation technique. As viruses, fungi and chemical weed control are factors that affect the plants in a stressful way and may harm the production by reducing the yield and diminishing the quality of cut flowers, we have concentrated our study on the physiological response of lily to such stressful factors and on elucidation of biochemical indicators of stress effects. These biochemical parameters can be used in order to develop a system for screening and selection of plants with high level of resistance to different stress factors.
Amount of free proline, activity of proteases and content of plastid pigments have been traced in dependence on developmental stage of Lilium sp., cv. Cunnecticut King. Magnified activity of proteases and elevated level of free proline in presence of Fusarium oxisporum f. sp. lilii and lily symptomless virus were established and a role of these metabolic fluctuations in stress response indication has been discussed. The influence of herbicides fluazifop and quizalofop on proteases and proline has been found in dose dependant manner. Viral and fungal infections diminished the content of chlorophyll while the effect of herbicides was slightly expressed.

Key words: fungi, herbicides, lily, proline, proteases, virus
Abbreviations: fluazifopbuthyl – fluazifop, F.O.L. – Fusarium oxisporum f. sp. lilii, LSV – lily symptomless virus, Pro – proline, quizalofopethyl – quizalof