In this report, B₉ treatment had no effect on the growing of rosette biennialScrophularia vernalis L.; it inhibited or slowed stem elongation. Applications of GA₃ to B₉ treated plants produced a significant increase of stem elongation, in relation to GA₃ treated plants. Plants treated with only GA3 failed to flower; otherwise, the flowering of vernalized plants was not altered by GA₃. Thus, B₉ effect on flowering was tested by using GA₃. B₉ by itself induced flowering, it increased inflorescence formation in vernalized plants without altering stem growth pattern in the most of cases. The induction or the stimulation of flowering brought about by B₉ was not reversed by GA₃; we may thus hypothesize that flowering by B₉ oannot be traced back to gibberellin biosynthesis.

The supply of nitrate nitrogen caused a marked increase in the rate of respiration of Japanese mint. Sodium azide strongly inhibited the rate of respiration at all the nitrate levels, but the inhibition was more marked at higher levels. Besides this, inhibition caused by azide treatment was less marked in older and nitrogen deficient tissues than in younger ones at higher nitrogen levels. The addition of sodium diethyl dithio-carbamate (DIECA), an inhibitor of copper containing enzymes resulted in an increase in the respiration of mint leaves which increased further with an increase in the nitrate supply. The same concentration of DIECA which stimulate the respiration of leaves caused an inhibition in the respiration of roots. The inhibition was greater at lower levels and decreased consistently as the supply of nitrate increased. The sensitivity of root respiration to DIECA observed with varying levels of nitrate indicated that unlike the leaf, the roots contain copper-containing enzymes which get decreased as the nitrate supply is increased. An increased supply of nitrogen up to 16 me NO₃^- -N was associated with an increase in respiratory quotient.

Trypsin and chymotrypsin inhibiting activities were detected in a "crude inhibitor" fraction of a lipid free cashew nut (Anacardium occidentale L.) meal. Both activities were shown to be heat resistant and not affected by pepsin at pH 3.0. Molecular weight distribution of tho trypsin inhibiting activity is similar to the known range of molecular weights for trypsin inhibitors of plant origin.
A "crude extract" of the cashew nut meal was shown to contain strong L-leucine-p-nitro-anilide and moderately strong α-N-benzoyl-DL-arginine-p-nitroanilide hydrolyzing activities. This last activity was strongly inhibited by the "crude inhibitor" fraction shown to contain trypsin and chymotrypsin inhibiting activities. The presence of this endogenous inhibitor-endo-peptidase system seems to indicate that the protein proteinase inhibitors of plant origin could be involved in the control of protein mobilization in the seed.

Tissue culture was isolated from the stem ofPopulus alba L. 'pyramidalis'. Callus formation was observed since November till March (1974),i.e. till the formation of calluses suitable for further subeultivation. The most vigorous growth was obtained with the callus culture cultivated on the nutrient medium of DIAZ-COLONet al. (1972) on which more than 11 g of fresh matter was produced after 30 d at the end of the first year of cultivation in darkness, with inoculum weight 1.5-1.8 g. A mild decrease in growth rate of the tissue culture was observed after the first year of cultivation. When illuminated, the originally yellow calluses turned green. The morphological and anatomical structure of the callus culture is also described and cell shape and cell size evaluated.

Growth ofSilene alba (MILLER) E. H. L. KRAUSE cells, as well as their peroxidase pattern and activity are studied. Cells were grown in the presence and absence either of IAA, or NAA or 2,4-D. The subculture is dependent upon the growth regulator used to sustain the growth of cells. For 14 days' passages, subculture is possible with 2,4-D (5 x 10^-7M) or NAA (10^-5M) but impossible with IAA or without any growth regulators. Cells grown using 2,4-D or NAA in the medium contain a smaller number of isoperoxidases and have lower activities than those grown using IAA or no growth regulator. The nature of growth substances does not affect the compartimontation of the peroxidase; in fact the bulk of the peroxidaso activity is always liable to the ionic wall bound fractions. Tho electrophorotic mobilities of peroxidase isoenzymes detected in the modium are not the same as those of tho eytoplasmic isoenzymes. Cell cultures grown with and without growth regulators show different patterns of modium peroxidase activities. Some forms are present both in cells and media and some other only in the media; this may indicate that there is some selection made in tho cells for retention of particulars forms; the others could be secreted as exoenzymes shortly after they are synthesized in the cells. The nature of the growth regulator used could act on the release of certain isoperoxidases. These results are discussed from the viewpoint of the correlation of isoperoxidase patterns with the possibility of subculture.

Barley embryos were treated by 0.1% colchicine for 30 min. Samples of root tips were fixed after 4 h, 8 h and 12 h. In the first sample,c-metaphases, normal metaphases and anaphases were present jointly. Inc-metaphases, chromosomes sometimes tended to make two groups with 7 chromosomes in each. In anaphases, lagging chromosomes, tripolar and multipolar anaphasos were found. No chromosomal aberrations were detected in anaphases and metaphases. No chromosome disturbances were found in root tips sampled 8 h and 12 h after colchicine treatment.

The initial strain ofDioscorea cell culture is characterized by a double-peak curve of mitotic activity, by dominance in the population of meristematic cells, by a great variety in the number of chromosomes and also by polyploidization in the process of cultivation.
After treatment with different doses of N-nitroso-N-methylurea (NMU) physiological parameters of the cell populations were found to change (dynamics of mitotic activity, ratio between types of cells). On passaging, physiological differences between the strains are levelled up.
The studied strains are characterized by different directions of cell selections,i.e. the control strain - towards polyploidization, and in NMU treated strains are stabilized on di- and triploid levels.

The effect on growth of an aliphatic acid isolated fromCastanea sativa cuttings was studied as well as its interaction with IAA. TheAvena coleoptile straight growth test was used. A growth inhibition was observed in a wide range of concentrations. The compound lowered or suppressed the IAA induced elongation of theAvena coleoptilo growth sections.

Nine categories (a-i) of seeds inIpomoea pes-tigridis showed diverse germination responses at desiccating high temperatures (65 °C). These nine "generative ecotypes" have assured the persistance of their race by producing sets of seeds suitable for a set of temperature conditions in the Indian desert, where high desiccation of seeds is a major natural controlling factor.

Net photosynthetic rate decreased sharply to zero in the range of water potential- 8.0 to -10.4 x 10⁵ Pa. The observed decrease in photosynthetic rate was due not only to the decrease in epidermal conductance, but also to the decrease in intraoellular conductance. Both conductances decreased in the same range of water potential. With decreasing water potential photorespiration rate decreased whereas dark respiration rate remained rather unchanged. Simultaneously CO₂ compensation concentration increased. These facts constitute an indirect evidence that water stress inhibited not only transport of CO₂ from atmosphere to carboxylation sites in chloroplasts, but also its conversion into photosynthates.

Tuber callus by subculture ofDioscorea deltoidea Wall, was grown with different sources of nitrogen on N-free Murashige and Skoog's basal media supplemented with a high level of kinetin (1, 3, 6, 9 and 12 ml 1^-1) and low concentration of auxin (0.01 mg 1^-1 2,4-D) for shoot bud differentiation. Shoot and root differentiation was observed only in the case of ammonium nitrate. Other sources of nitrogen failed to produce shoot bud differentiation except in the case of ammonium citrate where tissues were slight green in colour and were recognizable as pro-embryo.

The effects of red and far red illuminations were studied in spores of the dark germinatingPteridium aquilinum and that of the light dependently germinatingDryopteris filix-mas. Proteins were analysed by electrophoresis according to their molecular weights. The isoesterases were separated by gel electrofocusing. In both species we found two newly synthesized protein bands, probably controlled by the presence of active phytochrome. One of these seems to be identical, the other is different in the two species. Phytochrome control was also detected in the esterase isoenzyme pattern.

Benzylaminopurine (BA) caused an enhancement of chlorophyll and protein content and a reduced elongation of primary barley leaves. BA did not change the rhythmic pattern of¹⁴CO₂ fixation and activities of RuBP carboxylase, RuBP oxygenase, glycolate oxidase and phosphoglycolate phosphatase, but the enzyme activities were enhanced and the level of¹⁴CO₂ fixation was reduced. Light/dark¹⁴CO₂ evolution ratio was affeoted by BA only in older leaves. BA acts sequentially on the activities of photosynthetic and photorespiratory enzymes.

The minimum length of the mitotic cycle of root meristems of cultivated barley embryos and intact seedlings was longer than that measured by the construction of the labelled mitoses curve; it was 10-12 h for intact seedlings and 16 h for cultivated barley embryos. Action of colchicine on interphase was detected. Colchicine induces the increase of the frequency of prophases starting from the fourth hour. The most probable explanation is shortening of the S-phase. As the whole mitotic cycle duration is increased in comparison with that after³H-thymidine, it is most probable that G₁ phase duration is increased by colchicine treatment. Different cytogenetic effects of colchicine were analysed in detail. A basic difference between the response of root meristems of isolated embryos and of intact seedlings was found. In isolated embryos, the effect of 0.1% and 0.4% colchicine (i.e. blockage of anaphase movement, metaphase arrest and contraction of chromosomes) disappears within 2-5 h after removing the colchicine. In intact seedlings, the effect of colchicine is maintained for a considerably longer time. It leads to gradual accumulation of metaphases over 9 h after pulse treatment and this accumulation of metaphases leads to a gradual increase of the incidence of tetraploid mitoses starting from 10th - 12th till 22nd hour after the pulse. This is the reason why maximum frequency of tetraploid cells in root meristems of cultivated isolated embryos was 16 h after the pulse (i.e. at the beginning of their incidence) and it reached the value 5.4% while in seedlings the maximum was 22 h after colchicine treatment and it reached the value 38%.

Several improvements of the method of sap flow rate determination in full-grown trees elaborated by the authors are described. The method is based on heat balance with direct electrical heating of the xylem. The accuracy of the relationship for the calculation of flow rate was improved, the influence of unevennesses of flow in different annual rings was reduced. A method of extrapolation of the results obtained by measuring an individual xylem segment against the whole tree and of interpolation to a unit segment was elaborated, a simplified method of connecting the electrodes supplying the thermal input to the segment is described and an indicator of the relative water content of the xylem was derived.

Chosen species and cultivars(Nicotiana sanderae, N. glutinosa, N. otophora, N. paniculata, N. sylvestris, N. velutina, N. tabacum cv. Samsun, N. tabacum cv. Samsun - a dihaploid line, and an amphidiploid N.sylvestris x N tomentosiformis) were treated with adequate concentration of n-buthylmethane sulphonate. The anthers of M₁ plants were cultured on the medium of NITSCH 1969 plus 0.1 mg IAA/1. Special attention was paid to quantitative characteristics of androgenesis. Androgenesis occurred more often in the treated variants. The conclusions have been confirmed of a heterosis effect of adequate chemomutagen concentration at the diploid level (an increase in the number of androgenic anthers in the treated variants, and a decrease in the mean number of haploids per androgenic anther) in the broad range of the material. We have recorded a high androgenic ability in the amphidiploidN. sylvestris x N. tomentosiformis, and androgenesis inN. velutina for the first time.

Anatomical analysis of the sugar-beet seed ball indicates two possible ways for the entrance of water and oxygen during germination: cells from the operculum periphery and cells from the basal pore characterized by absence of lignin and a thin layer of cellulose. Impermeabilisation of these zones by vaseline considerably reduces the percentage of germination and stresses the major role played by the basal pore. This can also be confirmed by variation in the germination percentage when sowing the seed ball with the basal pore up or down to the substrate.

Alcohol dehydrogenase was prepared from 2-day germinating maize and 3-day germinating broad-bean seeds by ammonium sulphate fractionation of sodium phosphate extracts, chromatography onDEAE cellulose and Sephadex G-200. The activity of the broad beanADH amounted to182 800 units per mg protein, that of maizeADH 79 000 units per mg protein. Besides oxidation of a series of alcohols at pH optimum in the alkaline region and with KM equalling 10-2M, alcohol dehydrogenases isolated from both plants catalyze the reduction of acetaldehyde, n-propanal, n-butanal, isobutanal and crotonal at pH optimum in the neutral region with KM equalling 10-3M. The inhibition studies using fatty acids and chloride ions revealed that the oxidation of alcohols is inhibited competitively by both types of inhibitors, with inhibition constants of 10-2M and 10-1M, respectively. The inhibition in the presence of acetaldehyde is non-competitive since the inhibitors do not compete with acetaldehyde and do not form an enzyme-NADH-inhibitor complex, yet they obviously react with the enzyme-NAD product only, thus giving rise to an enzyme-NAD-inhibitor complex. These differences in the behaviour of inhibitors may be interpreted in the sense that the binding sites of ethanol and acetaldehyde as substrates for broad bean and maize alcohol dehydrogenases are non equivalent. The nonequivalency discussed in the text.

Penicillin caused elongation inhibition of mungbean (Phaseolus aureus L.) seedlings at concentrations above 100 mgl^-1. Inhibition of hypocotyl could be reduced to different degrees by manganese, pyruvate, succinate, fumarate, malate, GA₃, purines, pyrimidines and nucleosides, whereas the amino acids except cysteine were not effective. Penicillin inhibited neither elongation of wheat coleoptile sections nor the cell enlargement induced by IAA in this tissue. Thus penioillin inhibits intact seedling elongation probably through an Effect on cell division apparently without inhibiting cell enlargement.

During the germination of fenugreek (Trigonella foenum graecum L.) sulfhydryl groups rapidly declined in cotyledon and seedling axis, while peroxidase activity increased. Studies on purified isoenzymes showed that GSH was oxidized by the isoenzymes and was accomplished in presence of cofactors, Mn²⁺ and DCP along with H₂O₂ (0.01 mM). This reaction was found to be peroxidatic in nature. The oxidation was inhibited by catechol but was enhanced by malic acid.

Fusarium moniliforme var.subglutinansWr. etRg. causes malformations of mango inflorescences that finally fail to fruit. The host-cultivar Himsagar showed higher contents of total saccharides, chlorophyll and protein than the cultivar Bombai. Considerable loss in saccharides and chlorophyll contents and increase in protein content as a result of malformation of inflorescence was recorded in both the host-cultivars which progressed with time.