ACTA PHYSIOLOGIAE PLANTARUM Vol. 24. No. 4. 2002:371-378 Relationship between selected morphological, anatomical and cytological characteristics of leaves and the level of tolerance to herbicides in strawberry cultivars Jerzy Lisek 1, Hanna Habdas 2 and Stanistaw W. Gawrohski 3 1 Research Institute of Pomology and Floriculture, Pomologiczna 18, 96- t 00 Skierniewice 2 Research Institute of Vegetable Crops, Konstytucji 3 maja 1/3, 96-100 Skierniewice 3 Agricultural University, Nowoursynowska 166, 02-766 Warsaw Key words: calcium oxalate crystals, cuticle, epicuticular waxes, herbicides, stomata, strawber- ries, vacuole Abstract Foliar application of a mixture of herbicides containing phenmedipham, desmedipham and ethofumesate to the plants of nine strawberry culfivars revealed that there were differ- ences in the level of plant tolerance to the applied chemicals. Light, polarized light and scanning electron microscopy were used to explain differences in tolerance to herbicides. The sur- face of strawberry leaves and cells was examined for stomata, hairs, trichomes, surface structures, cucticle, vacuole and oxa- late crystals. The thicker the cuticle on the adaxial leaf surface, the thicker the layer of epicuticular waxes, greater number of large vacuoles and greater number of calcium oxalate crystals in epidermis cells were characteristic for cultivars with very good tolerance to herbicides. The cracking of epicuticular waxes layer was typical to cultivars with respectively low tol- erance to herbicides. Introduction The variations among strawberry cultivars in their sensitivity to phenmedipham, ethofumesate and their mixtures with other herbicides were reported by Clay and Abernethy (1976), Clay (1982), and Leiteritz and Pilz (1988). The authors; however, did not explain the causes of this phenomenon. In the opinion of other researchers varying sensitivities in strawberry to 2,4-D herbicide were caused both by the rate of its decarboxylation and, during absorp- tion, by its retention and inactivation as water- soluble compounds which were then stored in vacu- oles (Luckwill and Lloyd-Jones 1960). The toler- ance of strawberry plants to unfavourable external conditions, such as high salinity and drought, is re- lated to the presence of numerous crystals of cal- cium oxalate in plant cells (Goncharova and Dob- renkova 1981). An essential role in the absorption of herbicides is played by some of the plant morphological fea- tures. The stomata and hairs play only a relatively small role because the active substances are ab- sorbed mainly directly through the cuticle (Buko- vac 1976). Plant cultivars differ in their ability to absorb substances. The varied tolerance to aciflu- often in tomato cultivars, and others from the fam- ily Solanaceae, depends on the number of stomata and also, to a small degree, on the number of hairs per unit of surface area. However, the number and composition of epicuticular waxes and the cuticle 371