Higher³²P uptake per plant was found in the healthy resistant (R) alfalfa (Medicago saliva L.) plants when compared with the healthy plants susceptible (S) to the bacterial wilt, following the exposure of the roots of intact plants to the radiophosphate solution. The bacterial infection markedly decreased³²P uptake and radioactivity levels per dry matter in most organs of the R-plants on the day 8 and 14 after inoculation withCorynebacterium insidiosum whereas in the S-plants a decrease in³²P uptake was only found on the day 8.³²P leakage rate from the infected R-plant roots to the nonradioactive nutrient solution was higher than from the healthy ones on the day 8. At the same time³²P content in the organic P fraction was somewhat increased due to the infection in the R-plant roots, whereas³²P content in DNA was decreased. After foliar application,³²P distribution pattern was similar in the tissues of both the S- and the R-plants and was not affected due to the infection in the course of the 3rd week after inoculation. However, the bacterial infection markedly increased³²P translocation from the primary leaf to the rest of the R-plant.

Data point fields of values of the dependence of nitrogen and potassium concentration in shoot dry matter on dry matter weight in the course of the vegetation cycle at four stages of development of spring barley (Hordeum vulgare L. cv. Ametyst) plants were derived from a four-year-cycle of stationary field nutrition experiments at two localities. Three selection procedures of the boundary data are described. Graphical outputs and their subsequent mathematical expression enable an objective construction of regressive upper and lower boundary curves of the data point fields. The shape of the curves is characteristic of each investigated element. The position of the upper boundary curve can characterize the maximum uptake ability, that of the lower curve the maximum efficiency of utilization of absorbed nutrients, and their amplitude the requirement extent of the species or cultivar investigated. The boundary curves can be objectively constructed for individual nutrients from a sufficiently vast set of data from a very broad spectrum of ecological conditions (for example from stationary field nutrition experiments at various localities).

Decreasing substrate osmotic potential produced in seedlings ofVigna catjang Endl. (cv. Pusa Barsati) proportional decrease in relative water content and leaf water potential, increase in respiration rate, proline content, H₂O₂ content, and the activities of indole acetic acid oxidase, ascorbic acid oxidase, peroxidase and glycolate oxidase but decrease in catalase activity and glycolate content. Pretreatment with reducing agents like L-cysteine or reduced glutathione (10-3 M) caused lower decrease in the relative water content, leaf water potential and glycolate content and reduced the rise of respiration rate, proline content and H₂O₂ content and also the activities of aforementioned oxidative enzymes, except catalase activity which was increased. Such treatments also maintained the chlorophyll and protein levels and decreased the tissue permeability. It was concluded that the treatment ofVigna seedlings with reducing agents reduced the deteriorative changes and oxidative processes which are characteristic of water stressed tissue.

Two cultivars of pigeon pea (Cajanus cajan (L.)Millsp.) UPAS-120 and Parbhat were grown in the field under two irrigation treatments: no irrigation and irrigation when cumulative pan evaporation was equal to 50 per cent depletion of available water content in one metre root zone depth. Diurnal changes in leaf water potential and stomatal conductance were recorded on two daysi.e. October 1, 1979 and October 28, 1979 which corresponded to reproductive growth stage of the crop. Plant water potential decreased rapidly during the day up to about 15.00 and increased during evening hours. Higher leaf water potential was recorded in irrigated treatment on both dates. Adaxial and abaxial stomata differed in their response to water stress. Adaxial stomatal conductance started declining during early morning hours, however, abaxial conductance firstly increased up to 09.00 then decreased and increased again in the afternoon except in irrigated crop of cv. UPAS-120 on 28th October, where conductance never increased after 09.00. The reduced rate of stomatal conductance during day hours may be identified as one of the characteristics responsible for drought tolerance in pigeon pea.

Protease activity inSpinacia oleracea leaves, but not roots, increased when sodium sulfite, hydrogen peroxide and sodium azide, but not sulfuric acid, were injected through the petiole under light conditions. On the other hand, protease inhibitory activity in both the leaves and roots decreased by the injection.
Protease activity inRicinus communis leaves increased when hydrogen peroxide and sodium sulfite were injected through the petiole and kept for 4 h under light conditions. No visible injuries were caused to the leaf. On the other hand, protease inhibitory activity in leaves decreased by the injection of hydrogen peroxide.
Changes in the activity of protease caused the senescence of leaves such as chlorosis and necrosis which were observed with leaves injected with hydrogen peroxide after one week. These results suggested that in the healthy leaf, the protease inhibitor protects the cellular components from the protease.

The levels of gibberellin and cytokinin like substances are increased in mungbean (Vigna radiata L. Wilczek) seedlings by penicillin treatment. The possible role of penicillin in regulating the hormone levels in plant tissues is suggested.

Composition of complex lipid of chloroplasts of two cultivars of wheat and barley was determined at tillering, ear emergence and grain filling stages. The chloroplast lipids, MGDG, DGDG and PG were maximum at grain filling stage in both wheat and barley. PC content showed variations at different stages in both the crops while no significant changes were observed in PI concentrations at grain filling stage.

Exogenously applied IAA, GA₃ and Niagara (ethyl-hydrogen-1-propyl-phosphonate) activated dormant lenticel meristems of stem cuttings ofCedrela toona Roxb. Maximum activation was achieved by IAA at 0.5 mg ml^-1 concentration.

Malate dehydrogenase isoenzymes were studied in tenAllium species and in six cultivars ofA. cepa by isoelectric focusing in polyacrylamide gel with Ampholine pH 3.5-10.0. Using this method better resolution was obtained than by polyacrylamide gel electrophoresis. The number of MDH isoenzymes obtained by isoelectric focusing is from five to ten in the range of pH 3.65 to 6.75. MDH isoenzymes can be used for characterization on the level of species and cultivars (inA. cepa), but its use on the level of sections and subgenera is questionable.

Application of sodium chloride to crop plants in the culture medium leads to an increase in their endogenous content of free proline. There is a certain concentration of sodium chloride above which the proline content of the plants strongly rises (critical point). A relationship between endogenous sodium and proline contents could be found. In salt-sensitive plants (wheat) the critical point lies below that of salt-tolerant plants (barley). The critical concentration is not changed by certain alterations of the culture medium. The determination of the critical point by means of measurement of the proline concentration served as a basis for the analysis of the salt tolerance of crop plants.

After infection ofNicotiana tabacum cv. Samsun with tobacco mosaic virus (TMV) crude extracts from dark-green spots of upper leaves had a more strongly marked inhibitory effect upon TMV addedin vitro than crude extracts from the surrounding light-green tissue. Likewise, crude extracts from leaves ofNicotiana tabacum cv. Samsun showing recovery after infection with tobacco ringspot virus (TRV) were seen to have a marked inhibitory effect on TMV addedin vitro. The results obtained suggest that virus inhibitors are produced after virus infections not only in hypersensitive hosts but also in systemic hosts. Necrotizing processes are not an indispensable prerequisite of the production of virus-induced virus inhibitors.

The effect of silymarin complex on various types of expiants differing in their nutrition requirements was investigated. The growth of tumorous periwinkle (Catharanthus roseus [L.] G. Don) callus tissue was still identical with the control tissue at the silymarin concentration of 35 mg in 1000 ml of the nutrient medium. However, this silymarin concentration totally inhibited the growth of habituated periwinkle callus tissue; in the presence of 10 mg of silymarin, the growth of this tissue was similar to that of the corresponding tissue grown without silymarin. The growth of tobacco callus tissue (D-strain) requiring for its growth kinetin was reduced by 46.2% at the concentration 10 mg of silymarin in 1000 ml of nutrient medium, but its dry weight was increased by 21% in comparison with the control. Silymarin was most effective on the growth of callus derived from tobacco (Nicotiana glauca Grah:) stem pieces; callogenesis was observed in control tissue in 89.5% cases while in the presence of silymarin (10 mg) only in 48.6%. The primary callus growth was strongly inhibited, too (by 89.9%). The organogenesis onset was never observed on tobacco stem pieces cultured on a nutrient medium with kinetin and IAA in the presence of silymarin. When all types of expiants were transferred from the medium with silymarin on control medium, normal growth appeared very soon and the differences between the experimental and control expiants were smoothed out during two months. These results indicate that the observed changes might be due to the blocking of membrane system permeability leading to an insufficient supply of cells with nutrients and growth substances.

Seedlings of spring barley,Hordeum vulgare L. cv. Mirena, were grown in complete mineral solution (Richter's solution: R) or in solution lacking either phosphorus (R-P) or nitrogen (R-N) at low (LI: 28 W m^-2) or high (HI: 122 W m^-2) irradiance. Plants were kept in controlled environment chamber with 16 h photoperiod and 20 °C/15 °C day/night temperature. The experiment was terminated after 15 days when plants grown under R -N nad HI conditions died. The content of chlorophyll was estimated during the plant growth and content of nitrogen and phosphorus was determined at the end of the experiment. Deficiency of N and P induced higher chlorophyll formation at low irradiance. The efficiency of nitrogen and phosphorus utilization,i.e. ratio of plant dry mass/weight of N and P, respectively, per plant, was higher at HI in all experimental variants. Extremely high value of P utilization was found in plants grown under P-deficiency (850) as compared to the control (80). Understanding of interactions between the irradiance and deficiency of mineral nutrients is necessary for optimization of fertilization and understanding the mechanisms of action of mineral substances on plant structures and functions.

Eleven species of the genusAllium belonging to the sectionCepa, Phyllodolon, Rhizirideum, Melanocrommyum andAlliun ware investigated as to the presence of esterase isoenzymes by means of the gal isoelectric focusing which shows better resolution than polyaorylamide gel electrophoresis. In all examined species twenty six isoenzymes were found. The individual sections are well characterized by esterase isoenzymes revealed by this method, on the other hand, the differences, as shown by the Jaceard index, between the subganera are insignificant. Investigation of seven cultivars ofAllium cepa shows the isolated position of the cultivar Kaštická. These results are in full agreement with those found with use of the polyacrylamide gel electrophoresis and show the usefulness of gel isoelectric focusing for the solution of the chemotaxonomical problems.

Proteins of protein bodies from lupin cotyledons were subjected to affinity chromatography on a column of Con A-Sepharose. About 42% of them contained sugar component. Globulin fractions soluble and precipitated at pH 4.4 contained 77% and 66% of glycoprotein, respectively.

Incorporation of [¹⁴C]-glutamate into soluble proteins accounted for about 14% of the total glutamate uptake, while < 1% of the ammo acid carbon was incorporated into chlorophylla. Most of the remaining 85% of the glutamate was retained in low molecular mass pools. High uptake rates appeared to be related to a "shift-up" phenomenon, resulting from the addition of fresh media. Apparent turnover times, estimated from reverse isotope dilution experiments, varied from about 1 to 3.5 h for the soluble proteins and about 3 to 5 h for chlorophyll a. Rapid changes in glutamate to glutamine ratios, resulting from changes in irradiance, suggest that the intermediary metabolism of glutamate is regulated by irradiance.

Callogenesis was induced in mature embryos. The efficiency of induction and the growth of calli were dependent on 2,4-D concentration. No regeneration of buds or shoots was observed in 720 calli studied, but most calli showed intensive root proliferation on the regeneration medium. Most of the root meristem cells maintained diploid chromosome number. Only a low proportion (about 3.5%) of tetraploid cells was found. No other chromosomal changes were observed. Chromosomal variability does not contribute to the inability of calli derived from mature barley embryos to form buds and shoots.

Leaf form and stomatal characteristics play an important part in the strategy of tall fescue (Festuca arundinacea Schreb) to limit water losses. Transpiration rates of artificially rolled leaves measured by potometer at varying wind velocities support this assertion.

The effect of FeSO₄.7H₂O, Fe₂(SO₄)₃.9H₂O, disodium salt of ethylene-diaminotetraacetic acid, dihydrate (EDTA) and N-(2-acetamido) iminodiacetic acid (ADA) and their combinations on the androgenesis was studiedin vitro in tobacco (cv. White Burley) and datura (Datura innoxia Mill.). Simultaneously the reversibility and irreversibility of the morphogenic process leading to the conversion of the pollen embryoid into complete plant was followed.
Complete plants developed in anthers on media with trivalent iron, chelated trivalent iron, chelated bivalent iron, bivalent iron in the presence of ADA and of media with EDTA. The number of androgenic plants in anthers increased in the following order: Fe₃₊ < Fe₃₊ EDTA ≦ ≦ EDTA < Fe²⁺ EDTA. The marked brown colour of cultured anthers was due to the presence of trivalent iron in the medium. The androgenic development was most rapid on the medium containing only trivalent iron, slower on media with chelated iron and slowest on medium with EDTA. The viability of cultures with complete plants decreased in the reverse order. No complete plants grew on media without trivalent iron and without EDTA and on media containing only bivalent iron whereas globular embryoids arose and developed continuously on these media. The anthers reacted in the same way on both complete and minimal media. Isolated embryoids formed complete plants in corresponding variants on complete media only.
The development of pollen embryoids into complete plants was stopped by the transfer of globular and torpedo-shaped embryoids from medium with EDTA to the medium without EDTA. Isolated greenish cotyledonar embryoids continued to grow even on the medium without EDTA.

The data of Rowet al. (1961) on endogenous indoleacetylaspartic acid in tomato plants were reexamined. It was shown that two indole compounds were present in ethanolic extract of tomato stems and leaves. The predominating substance was concluded to be N-malonyltryptophan on account of its UV- and IR-spectra, colour reactions with the Ehrlich and Salkovski reagents and products of acidic and alkaline hydrolyses. The chemical nature of the second indole compound remained unknown. It differed from N-malonyltryptophan, N-aeetyltryptophan, indoleacetylaspartic acid and indoleacetic acid and may result from non-enzymatic transformation of N-malonyltryptophan.

Nitrate reductase (NR) activity of bothPisum sativum L. cv. Bonneville andTriticum aestivum L. cv. Sonalika seedlings was influenced by the phytochrome system. Short durations of "red" irradiation (R) increased extractable levels of NR whereas subsequent short "far-red" irradiation (FR) partially inhibited the R modulated increases. Qualitatively, a negative correlation existed between thein vitro NR activities andin vivo phytochrome levels inPisum. "Blue" irradiation (B) also increased extractable levels of NR inTriticum. A partial action spectrum study made by exposing excised etiolated leaves ofTriticum and shoot apices ofPisum revealed a maximum increase in extractable NR activities and tissue nitrate level (inTriticum) at 656 nm. A partial action spectrum for the extracted enzyme ofTriticum indicated that at 700 nm the level of activity was increased (as compared to dark controls) more than by R (656 nm), FR (725 nm) or B (425 or 450 nm) irradiation, although all wavelengths used increased NR activity.

In the natural monsoon environment, the leaves of Bala and Jaya cultivars experienced more than 10 per cent LWD for about 8 and 6 1/2 h in the diurnal cycle, respectively. The maximum LWD of around 14 per cent occurred between 14.30 to 15.30 at the time of minimum relative humidity (EH) and maximum air temperature (Ta). On the other hand, under controlled environment conditions, LWD values of both the cultivars remained below 10 per cent in the entire diurnal cycle. There was a close relationship between LWD and Ta (r = 0.90 for Bala and 0.91 for Jaya) as well as RH (r = -0.95 for Bala and -0.85 for Jaya). The results suggested that RWC values obtained on an interval of 30 min were not enough to observe more than the general trend as a complete recovery of stress achieved within 25 min of rewatering the stressed leaves. Calculations indicated that the determination of LWD with the techniques using excised leaf are likely to incur error as rice leaf may loose water at a rate of 0.3 MPa min^-1.

The degree of tolerance of two crown gall tumors and leaf calli ofArabidopsis thaliana to BUdR was compared. The nopaline producing teratoma tumor tolerated BUdR in concentration as high as 2.10^-4 M. The tolerance of octopine producing unorganized crown gall tumor to BUdR was lower, but both exceeded significantly the degree of tolerance to BUdR of untransformedA. thaliana calli, where 10^-5 M BUdR already show some inhibitory effect on the growth rate.