The herbicide terbutryn induced up to 11.3 % chromosomal abnormalities in cells undergoing meiosis inVicia faba. The mean number of pods/plant and the mean number of seeds/pod were considerably reduced, but the average seed dry mass was not or was only slightly affected by this herbicide. In C₂ plants chromosomal abnormalities were observed in few but significant numbers of cells.

Uptake and loss of irorganic phosphate was determined in sweet potato slices 'aged' in the presence or absence of gibberellic acid. Concentrations of uptake medium were varied from 0.1 to 1.2 mM. Slices, aged in gibberellic acid, took up considerably less phosphate, at all concentrations than control, whereas efflux from GA₃ treated discs was greater than control. Whether treated or untreated, kinetics proved to be biphasic hyperbolas. The results suggested an alteration in membrane permeability induced by gibberellic acid.

Kanamycin resistance gene was introduced into tobacco and Atropa belladonna cells by binary vectors, based on Agrobacterium, by means of inoculation of seedlings. The plasmid pGA472, which carries chimaeric kanamycin resistance gene expressed in plants was introduced by transformation into A. tumefaciens Bo542, harbouring pTiBo542 plasmid and A. rhizogenes 8196, carrying pRi8196 plasmids and the resulting two strains were used as binary vectors. Tobacco tumors induced by A. tumefaciens Bo542(pGA472) grew as undifferentiated, kanamycin resistant tissues. Those induced by A. rhizogenes 8196(pGA472) differentiated into transformed plants. When cultivated in vitro on 200 μg ml^-1 kanamycin medium, they showed yellow green sectoring, which was not selected out during vegetative propagation. Atropa belladonna tissues transformed by both A. tumefaciens Bo542(pGA472) and A. rhizogenes 8196(pGA472) differentiated plants which grew well on 200 μg ml^-1 kanamycin as green, non-sectoring plants; sensitive cells obviously did not divide at all. Selection of Atropa belladonna transformed tissues on kanamycin medium is much more efficient than selection of transformed tobacco tissues with introduced kanamycin resistance gene.

A comparative study of dark respiration and effects of high and low temperature on dark respiration in five greenhouse cultivated tropical and sub-tropical species was made. The respiration rates determined manometrically were low in all species. Respiration rates increased with increasing temperature. Low temperature treatment accelerated the rate of respiration at 25 °G except in two species. An attempt has been made to determine the critical and optimum temperature for these species. The respiratory behaviour of these species has been discussed with respect to their original habitats and prevailing environmental conditions.

Relationships among storage proteins in seeds from cultivars and primitive accessions of the four economically most important species ofPhaseolus - P. vulgaris, P. coccineus, P. acutifolius andP. lunatus - were studied.
Analysis of SDS-polyacrylamide gel electrophoretic patterns of storage seed proteins revealed common characteristics in the major groups of polypeptides forP. vulgaris, P. coccineus andP. acutifolius, while clear differences existed between thesePhaseolus species and P.lunatus.

An auxin binding protein fraction prepared by means of affinity chromatography on 2-OH-3,5-diiodobenzoic acid-Sepharose and gel filtration was used as antigen. The obtained rabbit antisera contained antibodies against the auxin, binding protein (ABP) and several contaminating proteins (nonABP). The nonABP could be separated on an appropriate affinity matrix omitting the TIBA analogue. After their immobilization on Sepharose antibodies directed towards contaminating, the proteins were isolated and immobilized, too. This IgGanti nonABP-Sepharose retains almost all contaminating proteins present in the specific eluates of the auxin affinity matrix. In a final affinity chromatography step on IgG-Sepharose a highly purified ABP could be eluted. This ABP was immobilized on Sepharose for the separation of monospecific antibodies against ABP (IgGanti abp). Using these antibodies the ABP could be localized within the outer epidermal cells of the coleoptile by immunofluorescence microscopy. From the inhibition of auxin induced elongation of coleoptile tissue by IgGanti abp it is concluded that the ABP is localized at the plasmalemma of the epidermal cells and that the ABP is involved in auxin action as a true hormone receptor.

Ultrastructural changes following increasing periods of water stress induced by means of polyethylene glycol 4000 (from 5 min to 18 h) were investigated in young epidermal cells of the primary roots ofZea mays. The sensitivity of the individual cell components to water stress was considered according to the time sequence in which their alterations appeared.
Endoplasmic reticulum (ER) and mitochondria proved to be the most sensitive cell components, their structure changing after 5 min of water stress. By 8 h of stress, the condensation of nuclear chromatin in some cells was apparent, preceding polyribosome degradation but not all the other changes of the stressed cells. Similar types of structural alterations appeared slightly earlier in the more differentiated epidermal cells. The rapid changes in the structure of ER and mitochondria coincided with the rapid decrease of water potential of the root tips and the immediate cessation of the root growth.

Distant hybridization of several species of the genusAllium was performed. It was found that disharmony of the time of flowering of the parents may be overcome by storage of pollen ofA. fistulosum at 40 % humidity and 0 °C. Protein patterns of parents and F₁ hybrids were compared using immunoelectrophoresis, esterase isoenzymes were evaluated by electrophoresis in polyacrylamide gel and isoelectrofocusing. Parents and relevant hybrids differ from each other. Certain differences were found between reciprocal hybrids.

The effect of CCC treatment on the GA and IAA contents of the hypocotyls of green and etiolated bean plants and on their distribution was studied. In the treated plants the GA content of the hypocotyls was higher than that of the control. On the application of CCC the distribution of the hormone content within the organ altered: in the basal part of the hypocotyls of the treated plants the hormone content increased. In the hypocotyls of the treated plants the IAA content was less than in the controls and it was accumulated in the basal part. The ethylene production of the aplcal and basal parts of the hypocotyls proved to be correlated with their IAA content.

Phenolic compounds l,2,3-trihydroxy-5-methoxyxanthone, l-hydroxy-3,5,6,7, 8-pentamethoxyxanthone, and l,8-dihydroxy-2,3,4,6-tetramethoxyxanthone predominate in the callus tissue ofCentaurium erythraea, their content increasing with culture age. By contrast, the contents of the derivatives of cinnamic, chlorogenic, and ferulic acids decrease or do not change. In the cell suspension culture ofC. erythraea a larger amount of xanthones is synthesized than in the callus from which the suspension culture was derived. The content of phenolic acids is lower in the suspension culture than in the callus, but a larger number of low-molecular-mass phenolic substances occurs in the suspension culture than in the callus tissue.

Electrophoretic separations of soluble proteins extracted from crown-gall tumors, normal calli, and leavesof Nicotiana plumbaginifolia were performed in order to detect pathogenic changes caused byAgrobacterium tumefaciens transformation. These analyses showed the appearance of new low-molecular polypeptides both in crown-gall tumors and in normal calli. The SDS-polyacrylamide gel electrophoresis as well as the gel electrophoresis in non-denaturing conditions were used to characterize their properties. At least some of them corresponded to the pathogenesis-related proteins reported inN. tabacum. Isoenzyme patterns of peroxidases and esterases also revealed a higher number and a deeper staining density of isoenzyrnes in crown-gall clones and normal calli compared with leaves, thus indicating an increased activity of enzymes in thesein vitro cultivated tissues.

The carbon balances of whole, 21-d old French bean plants (Phaseolus vulgaris L.) grown in standard nutrient solution (1K) and its modifications without (OK) or surplus (2K) potassium were calculated from the daily photosynthetic carbon inputs of individual leaves, and the daily respiratory carbon losses by individual leaves, stalks and petioles, and roots. Under the three K concentrations, maximum net photosynthetic rates (P_n) were found in the 2nd or in the 3rd trifoliate leaves, maximum respiratory rates (R_d) in the youngest, 4th trifoliate leaves; the P_n/R_d ratio decreased with leaf age. In all leaves of 2K plants, leaf dry masses and thicknesses, P_n, P_n/P_d ratios, and stomatal and intracellular conductances were lower than in OK and IK plants. Daily whole-plant net carbon gain was highest in IK plants, whereas in OK and 2K plants it was 98.0 and 81.3 % of IK, respectively. Similar values were found in the parameters of growth analysis, namely in net assimilation rates and relative growth rates.
No differences were found in water potential (Ψ _w ) or water saturation deficit (W_sat) in the OK, 1K and 2K plants sufficiently supplied with water or during wilting and resaturation. The decrease in Ψ_w to -0.97 MPa was associated with a 19.9 %, 31.4 % and 23.4 % decrease in P_n of OK, 1K and 2K plants, respectively, but no effect on R_d was found. In the three variants, the short-time effect of mild water stress was fully reversible.

In the cells of primary cortex in the roots of horse bean and of root cap of maize, vanadium induced striking changes in the shape of plastids,i.e. the origin of amoeboid, ribbonlike plastids and plastid protrusions.

The influence of blue, red and white light and gibberellic acid (GA₃) on gibberellin-like activity in tissue extracts of leaves, stems and roots was investigated during growth of pea seedlings (Pisum salivum L. cv. Bördi). Higher GA-like activity was found in leaves and stems of pea plants that were growing in blue light than in those under red or white light. Patterns of change of activity were different in leaves, stems and roots, and in GA₃-treated plants.

Strawberry plants have been regenerated from petioles and flower buds Petiole segments derived from strawberry plants(Fragaria vesca L. andFragaria xananassa Duch. cvs. Gorella and Redgauntlet) maintainedin vitro have been cultured on the Gambobg's. agar medium supplemented with 2,4-D (2 mg 1-¹) either alone or with kinetin or BAP (0.1 mg I-¹ or 1 mg I-¹). The calli thus obtained have been transferred to media differing from the first ones only by the nature and the concentration of the growth regulators used. One or two months later, shoots appeared on these calli. The influence of the media hormonal content on plant regeneration has been observed. Moreover, genotypic variations have also been investigated: the wild strawberry exhibited the greatest organogenic capacity.
Shoots have also been obtained from flower buds(Fragaria xananassa Duch. cvs. Fern, Hummi Gento, Gorella and Redgauntlet). In this case, shoots appeared directly on small calli derived from the peduncular base of the flower buds. These regenerations have been observed, without changes of media, on the Lee and de Fossabd's agar medium.

A number of markers characterizing the quantitative anatomical structure of the blade of the first and the third leaf were measured in young plants of eight cultivars of spring barley,Hordeum vulgare L.
The number of vascular bundles was in significant negative correlation with the mean distance between two adjoining bundles (r = -0.8) and also with their area in the cross section (r =-0.82). The proportion of the thickness of the epldermis in the thickness of the leaf and the proportion of the volume of the epldermis in the total volume of the leaf was in the order of 0.25 to 0.30. The proportion of the volume of the photosynthetic tissues in the total volume of the first (or the third) leaf fluctuated from 0.51 (0.53) to 0.58 (0.63). The thickness of the leaf blade and the thickness of the particular leaf tissues and their relative voluminal proportion significantly differed in the basal (B), middle (M), and aplcal (A) parts. No significant correlations were found between the values of the parameters of the first and the third leaf. Significant differences between genotypes concern most of the measured characters. No tendency to unequivocal changes between older and new genotypes could be inferred from the results obtained.
The results are discussed with regard to the necessity of a quantitative description of anatomical structures for the elucidation of physiological processes.

Two peptide hydrolases - one active at pH 7.0 and the other at pH 3.4 (SH-dependent) were detected in ragi (Eleusine coracana Gaertn. cv. PR 202) leaves. The absolute activities of both acid and neutral peptide hydrolases were move or less stable in attached leaves and exhibited a mild rise in excised leaves, whereas the specific activities exhibited a significant rise. Light and growth regulators were ineffective in changing the course of absolute activity whereas cytokinins stimulated specific activities of both acid and neutral peptide hydrolases. Though the rates were different, protein decline was positively correlated with the changes in activities of peptide hydrolases. Cycloheximide retarded chlorophyll and protein decline and also prevented the rise in peptide hydrolases. Peptide hydrolases thus do not have an active role in senescence.