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.

D,L-indol-3-yllactie acid was applied at concentrations 0.2 - 20 mg 1^-1 (10^-6-10^-4M) to the roots of 3-d-old intact maize seedlings grown in the dark and in the light. By day 3 after application, ILA at lower concentrations (0.2-1 mg l^-1) caused slight increase in the mass of etiolated plants, mainly roots. Shoot and root length was not increased. ILA at concentrations equal to, or greater than, 2 mg 1^-1 reduced the length of the main roots and from 10 mg 1^-1 on also the length of the shoots. In contrast, root mass was decreased by higher ILA concentrations to a lesser extent than shoot mass. The response to ILA application of etiolated seedlings differed from that of the seedlings grown in the light only at 20 mg 1^-1. The inhibitory effect was more pronounced in the case of quickly growing etiolated plants.

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.

Six thousand anthers ofSecale cereale cv. Dańkowskie Zlote and inbred lines L214 L215 and L258c/5, in the uninuclear microspore were cultured over a period of three months on Murashige and Skoog nutrient medium supplemented with IAA (1-2μg1^-1), kinetin (0.2 to (1.0μg1^-1) and 2,4-D (0.5-2.0μg1^-1). First divisions of microspore were observed after 7 days. In the course of 10 weeks, 4 albino tic embryos at the cotyledon stage were observed that died away in the course of further culture. The course of androgenesis was regular in inbred lines and irregular in rye cv. Dańkowskie Ziote. The efficiency of androgenesis and the amount of observed globular structures in anthers were also dependent on the genetic potency of the material. Inbred lines did not show any greater viability of embryos.

Immunodiffusion tests were used for studying protein composition of apical buds ofRudbeckia bicolor andPerilla nankinensis during their transition from vegetative to reproductive state under inductive photoperiodic conditions or GA₃ treatment. In both species the induced buds differ from the vegetative ones in the presence of specific proteins (P): P1, P2, P3 appear inRudbeckia apical buds 2, 8, 16 d after the start of inductive treatment; P4 appears inPerilla apical buds 6 d after inductive treatment. P1, P2, P4 are revealed in induced buds in the early period of apex development when morphogenetic changes are not yet present. The similarity between antigenic spectra of induced buds and of those treated by GA₃ appears only inRudbeckia. These observations support the hypothesis of a change in gene expression at floral evocation.

Changes in the different forms of the total activity of peroxidases (soluble, ionically and covalently bound), in the soluble isoperoxidase composition, and in the content of protein and chlorophyll during growth and senescence of the intact primary leaves of spring wheat were studied. The forms of peroxidases are in inverse relationship to the growth and increase during development and senescence, especially towards the end of senescence. The activity of peroxidases does not follow the physiological age of wheat leaves during the whole period of vegetation unlike the contents of protein and chlorophyll. The intensity of anodic and cathodic peroxidase isoenzyme bands 1 and 5 increases during senescence, but anodic bands number 2 and 4, cathodic bands 2 and 3 decrease. Changes in the activity of peroxidases and in the content of protein and chlorophyll as indicators of senescence are discussed.

During the search for compounds with insect juvenile hormone activity, the biotransformation of 2-(4-methoxybenzyl)-l-cyclohexanone, of 2-(4-methoxybenzyl)-l-cyclohexanone ethylene acetal and of both isomers of 2-(4-methoxybenzyl)-l-cyclohexanol by plant cells was examined. The compounds were metabolized by cell suspension culture of Solatium aviculare Forst. The reaction conditions were optimized and the metabolic products isolated and identified. A scheme of biotransformation pathway has been proposed.

The content and changes in the activity of phosphogluconate dehydrogenase were followed in leaf tissues of tobacco plants infected with the potato virus Y (PVY) in the acute phase of infection. The activity of the enzyme was higher in virus-infected tissues during the entire experimental period compared with the values found in healthy control plants in both crude homogenate and partially purified enzyme preparation. The courses of the activity curves of both the crude extract and partially purified enzyme preparations were consistent and correlated with the reproduction curve of the virus. These results suggest that increased activity of the enzyme was a result of its coarse regulation and indicate its immediate involvement in"de novo" biosynthesis of the virus via the oxidative pentose phosphate pathway.

Adventitious root formation in stem cuttings of mung bean was enhanced by ethrel, which had an additive effect when employed simultaneously with indolebutyric acid (IBA). Abscisic acid (ABA) did not influence the number of roots per cutting whereas gibberellic acid (GA₃) and kinetin were without effect on rooting at lower concentrations but were inhibitory at higher concentrations. Nevertheless, all three of these chemicals showed synergistic interactions with IBA and/or indol-3-ylacetic acid (IAA) and thereby significantly promoted root formation. A localised application of morphactin to the epicotyl of cuttings totally inhibited root production irrespective of which of the foregoing growth regulators were suppliedvia the hypocotyl. Morphactin application also prevented root formation in cuttings treated with vitamin D₂. The various growth regulators employed had differing effects on growth of roots but there was no simple relationship between their effects on root formation and subsequent root growth.

The content of endogenous cytokinin-like substances and the release of ethylene were determined in leaves of different insertion of sunflower plants during their ontogeny. The content of cytokinin-like substances was highest in the leaves on the middle part of the stem (that is in leaves just before full expansion), with a decrease occurring both towards the base and the apex of the stem, when followed at four growth phases (vegetative plants, plants with inflorescence diameter up to 0.5 cm, plants with inflorescence diameter up to 3 cm, and plants in flower). Changes in the content of cytokinin-like substances during the ontogeny of the leaf also corresponded to this pattern. Data obtained with the leaf at the third node from the basis of the stem showed that the level of cytokinin-like substances first sharply increased, and then after reaching maximal value (at the time when leaf blade area reached approximately 70 % of the final value) slowly and continuously decreased.
The highest amount of ethylene released from the leaves was recorded in basal leaves and then also in apical leaves, whereas the leaves with the largest blade area situated at the central part of the stem released the lowest amount of ethylene. This pattern was repeatedly found at all four selected growth phases of sunflower plants.

Salinity had generally little influence on the water content of different parts of cowpea(Vigna sinensis L.), calabrese(Brassica oleracea L. var.botrylis) and red radish(Raphanus salivus L.) plants. Salinity showed a promotive effect on the growth of cowpea, while in calabrese the effect was either promotive or depressive depending upon the concentration of the NaCl, and in red radish plants salinity progressively suppressed growth.
Total nitrogen, phosphorus, potassium and sodium contents of cowpea leaves were not affected by salinity treatments, while in calabrese and red radish leaves the contents of N, P and K were generally decreased as the salinity level increased. Gibberellin (GA₃) applied to salt-treated plants had either a stimulatory or inhibitory effect on the growth, water content and contents of N, P, K and Na in the leaves depending upon the plant type, the concentration of GA₃ and level of salinity.

Benzylaminopurine and thidiazuron stimulated shoot proliferation ofTilia, Sorbus andRobinia. Low concentration of BAP (0.2-1.0 mg I^-1) promoted axillary bud formation and shoot elongation. Thidiazuron displayed high cytokinin activity at very low concentrations (0.002-0.05 mg I^-1). Shoot number induced on media containing thidiazuron was large. Numerous shoots were produced on the media containing BAP together with thidiazuron. Shoots produced on media containing thidiazuron or BAP together with thidiazuron rooted after transfer to medium supplemented with low concentration of auxin (IBA or NAA).

Crown galls and hairy roots were induced inin vitro cultivated seedlings ofAtropa belladonna by differentAgrobacterium tumefaciens andA. rhizogenes strains. During furtherin vitro cultivation, tumors and hairy roots showed high differentiation ability which persisted for at least one year ofin vitro culture. Only root cultures, induced by Ri plasmid A4, synthesized detectable amounts of alkaloids.

Effect of abscisic acid on cell permeability in leaves ofIresine u allisi hort. and roots ofBeta vulgaris L. were examined. An increase of betacyanin leakage from leaf cells was shown by ABA at 10^-4, 10^-7 or 10^-9 M concentrations in water solution at 25 °C. The efflux of batacyanin from tissues did not change during the joint action of ABA and PEG 1000. ABA could lower the betacyanin leakage fromIresine leaves and beet-root slices under severe osmotic stress, as was found by deplasmolysis. The results suggest that ABA elicits some alteration in density of tonoplast membranes under dehydration.

Methyl jasmonate (JA-Me) at a concentration of 0.5% in lanolin paste totally inhibited bulblets formation induced by benzyladenine in intactMuscari bulbs. Lower concentrations of JA-Me delayed development and growth of bulblets induced by benzyladenine. It seems that methyl jasmonate acts as a powerful inhibitor of cell division induced by cytokinin in used test. In comparison with methyl jasmonate, abscisic acid did not show an inhibitory effect on bulblets formation induced by benzyladenine, even in a higher concentration.

A cabbage variety with particularly strongly developed leaves and extremely shortened stems (tight heads) was treated during the first year of its development with growth retardants (CCC and CEPA, Ethephon) at different concentrations. A 4-fold treatment with CCC, CEPA or a mixture of both proved to be most effective Leaf growth was inhibited by this treatment (head mass decreased) but stem growth increased. Only in treated plants the bud of the stem apex could break through the leaf sheath and develop generative stem. The results are discussed as examples of correlative relations between leaf and stem growth.