A mathematic model of loaf water potential daily dynamics was employed to study the relationship between this characteristic and soil moisture for the speciesQuercus cerris,Acer campestre andCarpinus betulus. It was found that when evaluating the availability of soil water for a plant it is necessary to consider the vapour pressure deficit which remarkably affects the relationship between the soil moisture and leaf water potential. A quantitative description of the dependence between the leaf water potential and soil moisture enabled a physiological interpretation of the limit values of soil moisture - permanent wilting and reduced availability of soil water for the plant - as well as evaluation of the drought resistance of plants.

The effects of foliar application of morphactin (0, 10, 50 and 100 ppm) onPennisetum typhoides (cv. HB3) have been studied under different soil moisture conditions (0.3, 3 and 9 x 10Pa tension). Morphactin application reduced the plant height, increased the tillering and leaf number of the main shoot and adversely affected the growth characters associated with the grain production. The overall performance of plants was not improved by morphactin treatment under low moisture regime and it did not impart any efficiency of water use for grain production. Findings on the phosphorus and potassium levels of the shoot tissue suggested a possibility of its interference in the nutrient uptake process.

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).

Plants were regenerated from mesophyll protoplasts of axenically growing plants of four dihaploid clones and five tetraploid cultivars ofSolanum tuberosum L. andSolanum phureja Juz. etBuk.

The dependence of electric conductance (admittance) of the stem on seedling water content (on the relative water content related to dry matter, or on the water saturation deficit, respectively) was followed in spruce and pine seedlings. The dependence was statistically highly significant and strong:r = 0.80 when individual plants were evaluated andr = 0.97 when mean values of twenty-seedlmg sets were taken into account. Electric conductance values can be used as a substitute) for water content determinations in plant tissues under defined conditions, although tho exact interpretation, especially of absolute values of those quantities with regard to their capacity component, remains to be offered.

A pot culture experiment was performed to evaluate salt tolerance potential ofSesbania aculeata Poir. The plant can tolerate salinity levels up to electrical conductivity (ECe), 10 mS cm^-1 and at 15 mS cm^-1 thero is about 40% reduction in dry matter production. The analysis of inorganic constituents in different plant parts revealed that the plant has the capacity to regulate sodium uptake under saline conditions and chloride uptake always exceeded that of sodium. The potassium: sodium ratio is also maintained at a fairly constant level in leaflets while it is reduced in leaf rachis, stem and roots. Salt stress caused accumulation of calcium and magnesium in all plant parts. A considerable decline in phosphorus uptake was observed due to salinity. Iron was found to be accumulated more in salt stressed roots only. Nitrogen accumulated in both roots and leaves while considerable proline accumulation was observed in leaves of salt stressed plants. The amount of soluble sugars was increased in roots and leaves due to salt stress, while starch content of roots decreased. Those changes induced by salinity are discussed in relation to salt tolerance capacity of the plant.

Nitrate concentration required for maximal extractable level of nitrate reductase (NR) inWolffia varies with the conditions prior to the nitrate treatment. Maximal enzyme activity is obtained at 2 mM nitrate concentration with asparagine grown plants and at 15 mM with nitrate grown. Both the level of enzyme activity and nitrate uptake by the tissue are increased by irradiation. The radiant energy induced increase in enzyme activity is not due to photosynthetic activity alone. An effect of radiant energy at the membrane level is sug gested. The extracted enzyme, which is labile, is protected and activated by NADH at 0 °C.

Considerable changes in the activities of phosphoenolpyruvate carboxylase and ribulosebisphosphate carboxylase were found inNicotiana tabacum cv. Sarasun plants infected with TMV. Ribulosebisphosphate carboxylase is inhibited at the time of maximum TMV reproduction, but its decreased activity is at the same time partly compensated by phosphoenol-pyruvate carboxylase in the shoots of infected plants. The pattern of activity of this enzyme nearly exactly reflects the pattern of reproduction of the tobacco mosaic virus.

During high altitude acclimatization soluble sugar contents were highest in temperateArtemisia species when grown at 550 m and tropicalArtemisia species at 3600 m in the active growth phase. During the senescence in all the species the soluble sugar contents were low in plants grown at 3600 m.
The starch content was low in the leaves of the tropical and sub-temperate species when grown in the alpine zone but in the temperate species a significantly higher amount of starch was observed at 3600 m altitude.
The amount of lignin acids was lower in the tropical and sub-temperate species but higher in the temperate species when these were grown at a higher altitude.

Three different treatments by calcium (10²M), namely seed treatment, foliar spraying and their combination were applied on field-grown rice (Oryza sativa L. cv. Ratna) under both water stressed and non-stressed conditions in the course of plant development. The relative water content and leaf water potential decreased with increase in age of stressed and non-stressed plants. Pretreatment of seeds with Ca improved the water status of the plants most prominently at the vegetative stage but the effect gradually faded away with plant development. The foliar spraying by Ca was more effective in improving the water status of the plants at the reproductive stage. The combined Ca treatment significantly improved water status of the plants both at the vegetative and reproductive stages. The contents of chlorophyll and protein decreased and the activities of protease and RNase increased in the course of plant development in both non-stressed and even more in stressed plants. Ca treatments of seeds or plants or their combination inhibited the decline in chlorophyll and protein contents and the rising trends of protease and RNase activities, the combined treatment being most effective. During plant development free proline content increased significantly more in water stressed plants. In non-stressed plants there was a marked increase in the free proline content at the mature fruit stage. Ca treatment inhibited the rise of free proline in stressed plants. A significant reduction in yield components and yield of the crop in water stressed plants was increased by Ca treatment.

Seedlings of spring barley,Hordeum vulgare L. cv. Mirena, were grown in a controlled environment chamber at high (HI: 122 Wm^-2) and low (LI: 28 Wm^-2) irradiance in the complete Richter's nutrient solution (R) or in solution lacking either phosphorus (R -P) or nitrogen (R -N). The experiment was terminated 15 days after sowing when plants (R-N) at HI ceased to grow. At that time the dry mass of one plant was 449.8 mg, 145.7 mg and 116.8mg at HI and 203.4 mg, 110.1 mg and 91.0 at LI for R, (R-P) and (R-N), respectively. Deficiency of P and especially N reduced the size of loaf area more under HI than under LI conditions. Specific dry mass of leaves was the highest in R-N plants. The values of relative growth rate and assimilation rate are presented. Interaction of the effects of deficiency of mineral nutrients and irradiance during cultivation should be analyzed in further experiments for determination of optimum conditions for utilization of mineral nutrients.

Red light (660 nm) break which cancels the floral inductive effect of the dark period brought about a transitional rise in the level of free IAA in the shoot ofChenopodium rubrum. The higher content of IAA was then found in treated plants at the beginning of the following photoperiod, too. The red light treatment did not change the phase of endogenous rhythm fluctuations of free IAA.

The content of bound proline sharply increased in proteins of different organs of young plants of winter rape and winter wheat exposed for 72 h to temperatures from 0 to 2 °C while it decreased only in root tips of wheat plants. Free proline which at 20 °C occurs in all plant organs only in trace amounts, accumulated considerably after 72 h exposure to low temperatures in the above-ground organs and only slightly in the roots. Free proline did not accumulate during the first 24 h at 0 to 2 °C in detached leaves of winter wheat but it was incorporated into newly synthetized proteins in which proline content increased after 6 h incubation to its maximum ( + 11.75% in comparison to control); the content of free glutamate sharply decreased during the first 6 h of incubation and the accumulation of bound glutamate was belated in comparison to that of bound proline. Sucrose infiltrated into detached leaves of winter wheat strongly stimulated proline incorporation into proteins at low temperatures, but it did not influence glutamate incorporation. The results suggest that the main reason for thede novo proline biosynthesis during the first six hours of hardening of the plants is the synthesis of proteins rich in proline; free proline accumulates later predominantly in the above-ground organs as a surplus. The above-ground organs are dehydrated in the course of the hardening process approximately to the same extent both in the light and in the dark, but proline content increases much less in the dark than in tho light.

Uptake of phosphate ions by 1 mm segments of isolated maize root cortex layers was studied. Cortex segments (from roots of 8 days old maize plants) absorb phosphate ions from 1 mM KH₂PO₄ in 0.2 mM CaSCO₄ at the average rate of 34.3 ±3.2 μg P_i g^-1 (fr. m.) h^-1,i.e. 0.35± 0.02 μmol P_i g^-1 (fr. m.) h^-1. Phosphate uptake considerably increases after a certain period of "augmentation",i.e. washing in aerated 0.2 mM CaSO₄. This increase is completely blocked by the presence of 10 μg ml^-1 cycloheximide.
The relation of uptake rate to phosphate concentration in the medium was shown to have 3 phases in the concentration range of 0.02 - 40 mM. Transition points were found between 0.8-1 mM and 10-20 mM. Following K_m and V_max values were found: K_m[mM] : 0.37 - 3.82 - 27.67 V_max[μg P_i g^-1 (fr. m.) h^-1] : 3.33 - 39.40 - 66.67
We have found no sharp pH optimum for phosphate uptake. It proceeds at almost constant rate till pH 6.0 and then the uptake rate drops with increasing pH. At low phosphate concentrations (1 mM) the lowest uptake rate was found at 5 and 13 °C, while the uptake is higher at 5 °C than at 13 °C at phosphate concentrations higher than 1 mM. At these concentrations uptake rate at 35 °C is lower than at 25 °C.
Phosphate uptake considerably decreased in anaerobic conditions. DNP and iodoacetate (0.1 mM) completely blocked phosphate uptake from 1 mM KH₂PO₄, while uptake from 5 and 10 mM KH₂PO₄ was left unaffected by these substances. The inhibitors of active - SH groups NEM and PCMB inhibited phosphate uptake: 10^-3 M NEM by 81.6%, 10⁴ M NEM by 42% and 10^-4 M PCMB by 42%.

Stem tips ofSpinacia oleracea were isolated and grown in sterile culture, with Sandoz 9789 added to the medium. Although the herbicide provoked a complete loss of all chloroplast pigments, developed shoots were able to flower, in response to long days; in short days flowering was inducible by adding gibberellins. Sandoz 9789 decreased the elongation of stems by up to 30%; the percentage of flowering plants in culture was also decreased. However, among those plants that flowered, the majority were male, so that Sandoz 9789 produced a shift of the sex ratio toward maleness.

The activity of L-tryptophan synthase (TS, E.C.4.2.1.20) was comparedin vivo in seedlings of plants high in L-tryptophan (L-trp) (pea and kohlrabi) and low in this amino acid (maize). In maize the TS was studied both in the normal and in the opaque-2 genotype that forms an endosperm richer in essential amino acids. The activity of TS was determined on the basis of the increase in radioactivity of the chromatographically purified L-trp-¹⁴C, synthetized after vacuum infiltration of L-serine-¹⁴C-(U) and ineubation for 24 h. As regards the TS activity in seedlings, maize is comparable to pea and kohlrabi; in contrast to this TS is less active in pea seedlings, which can be attributed to the presence of TS inhibitor (CHEN and BOLL 1969). In ripening maize kernels and leaves adjacent to the ear the TS activity is about 20 times lower than in seedlings. The differences in the activity of TS in the genotypes of maize could not be detected, even at the period of seed ripening. Therefore the differences in L-trp content in the investigated plants cannot be explained by a differing activity of TS. TS is probably not the determining regulator of L-trp level in plants, its activity is relatively high even in plants low in L-trp.

The biosynthesis of L-tryptophan (L-trp) from anthranilic acid-¹⁴C (AA-¹⁴C) in. undamaged organs of the seedlings of kohlrabi and pea, with high L-trp content and ma ze plants, with low L-trp content was compared. As for maize the experiments were carried oiut with normal and opaque-2 phenotypes, both with the seedlings and with the ripening kernels. AA-¹⁴C is metabolized in the plants to L-trp pool (i.e. free and bound L-trp, and secondary metabolites) and to glycosyl esters of AA (i.e. to simple glucosyl ester in pea and kohlrabi and more complex glycosides in maize). In maize seedlings L-trp-¹⁴C is synthesized relatively less. (40% in the 1st and 2nd leaf and 33% in the 3rd leaf of the total radioactivity of the incorporated AA-¹⁴C is transferred into the L-trp-¹⁴C pool after 24 h) than in kohlrabi (52% in the hypocotyl and 85% in the cotyledons) and in pea (58% in the 1st and the 2nd internode and 85% in the 3rd and the 4th internode). Thede novo formation of L-trp-¹⁴C is stoped earlier in maize (after 5 h) than in kohlrabi (after 15 h). The level of free L-trp-¹⁴C is relatively low ill maize (15% and 13% of the total radioactivity of the incorporated AA-¹⁴C is converted to free L-trp-¹⁴C and remains in this form after 24 h) in comparison with kohlrabi (31% and 60%) and pea (30% and 49%). In spite of this the formation of L-trp-¹⁴C from AA-¹⁴C is sufficient in maize to incorporate L-trp both into the proteins and into a secondary metabolite that is not yet defined. At the period of seedlings the incorporation in maize of L-trp into the proteins (11% and 10% of the activity of the incorporated AA-¹⁴C) is comparable with that in kohlrabi (11% and 17%), and it is maximum in pea (29% and 36%). Maize, at the stage of germination, thus forms proteins rich in L-trp. The formation of free L-trp is approximately ten times lower in ripening kernels and in the leaves adjacent to the ear and it further decreases in the course of the ripening of the kernels. Although the activity of the biosynthesis of the AA-¹⁴C → L-trp-¹⁴C pathway is relatively lower in maize than in kohlrabi and pea, this pathway is most responsible for the differences in the content of L-trp in these plants.
Neither amitrol nor histidine affected the biosynthesis of L-trp in kohlrabi; the interaction of the biosynthetic pathways of L-trp and histidine known in microorganisms is thus not important in a higher plant.

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.

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.

A new undescribed yellows-type disease ofGypsophila paniculata L. was found. Since a stunted growth is the predominant symptom the disease has been termed stunting. Electron micrographs of ultrathin sections revealed numerous mycoplasma-like organisms in diseased phloem tissues. Attempts to maintain the diseasedGypsophila plants for further investigation of this disease failed for the present in spite of all applied modifications in nutrient media.

Supply of KNO₃, NH₄Cl or NH₄NO₃ to the maize seedlings increased total chlorophyll and carotenoids (over zero nitrogen control) amounts per fresh matter unit of the primary leaves. The increase was most apparent when the pigment level in control plants started declining,i.e. between days 14 and 16. Supply of inorganic nitrogen increased pigment synthesis in excised leaf segments from dark grown seedlings, although the increase during a 24 h incubation was not as high as with either glycine or glutamine. Salicylic acid at 0.01 to 1 mM concentration increased and at 10 mM lowered the pigment biosynthesis. The increase at lower concentrations of salicylic acid was unaffected by KNO₃ but it was suppressed by NH₄Cl. When 12-day seedlings were transferred to the dark, total chlorophyll and carotenoids declined appreciably, but the supply of inorganic nitrogen protected them from decline to same extent. Thus inorganic nitrogen, especially the nitrate, is more important in protecting from degradation of chlorophyll and carotenoids than in increasing their biosyntheses.

Nitrate reductase level in leaves of pea plants is higher than in roots despite of the lower content of endogenous nitrate. Addition of ammonium ions to nutrient solution containing nitrate decreases nitrate reductase level in leaves estimatedin vivo while its level estimatedin vitro is increased.
Glutamine synthetase (GS) level in roots decreases during short (24 and 48 h) and long (14 d) term cultivation of seedlings in solutions containing ammonium ions. This decrease occurs in leaves only after the long term influence of ammonium ions. Level of this enzyme is higher in plants grown in the presence of nitrogen (ammonium and nitrate) as compared to those grown without the nitrogen.
Level of glutamate dehydrogenase in roots is increased after both short and long term cultivation of plants in the presence of ammonium ions.

Spring barley cv. Spartan was cultivated in a complete and nitrogen lacking Richter's solution. In other experimental variants the nitrogen was omitted after six days of cultivation in the complete nutrient solution or the nitrogen lacking solution was replaced with the complete solution after the same period of time. Anatomy of the second leaf blade was quantitatively analyzed after 12 days of cultivation. Continuous nitrogen deficiency resulted in thinning of the blade, reduction of the cross-section areas of the blade, vascular bundles and sclerenchyma region. The most sensitive reaction to the nitrogen deficiency was that of assimilation parenchyma. The values of characters of the other two investigated variants were between the control and permanent nitrogen lacking variant.

Photoperiodic responses of seedlings of long-day plantBrassica campestris L. cv. Ceres were investigated at different ages and varying length of inductive period. It was found that photoperiodie response increased with age. All plants flowered after one inductive cycle beginning with a light-period of 16h, but remained in the vegetative phase when kept under short-days (16h darkness, 8h light).
Both auxins (IAA and NAA) and cytokinins (kinetin and benzyladenine) inhibited flowering when applied to the plumule or via the roots immediately before the inductive photoperiod. This inhibitory effects was confined to bud formation, whereas the rate of leaf initiation remained mostly unchanged. Only high concentrations of growth substances also affected the growth of roots and leaves. These results agree, in general, with the effects of growth substances in the short-day plantChenopodium rubrum.

On squash preparations of anthers from pollen fertile and sterile plants of sweet pepper (Capsicum annuum L. cv. Severka) callose envelopes of microsporocytes, stained specifically with resorcin blue, were investigated microscopically. During normal course of microsporogenesis in fertile plants the envelopes remained intact up to the stage of microspore tetrads. Then callose begins to dissolve, and that from individual microspores towards the envelope periphery. In sterile analogues of the same cultivar the callose breakdown occurred precociously, usually in the course of the second, but sometimes as early as the first meiotic division of PMCs. Having completed meiosis sporadic microsporocytes formed microspore tetrads. Most PMCs contained an undivided four-nucleate protoplast rimmed with a narrow or wider unstained zone of dissolved callose. In certain cases more condensed callose septa pointing to the furrows on the surface of the PMC protoplast were well-observable in this lytic zone, as a residuum of normal mechanism of tetradogenesis.

Protein content, total and specific peroxidase activity and isoperoxidase patterns were determined in crude protein preparations from individual parts of field-grown wheat (Triticum aestivum L., cv. Jubilar). Protein content in roots, leaves, and stalks increased at the beginning of ontogenesis and then decreased from 6th, 9th, and 10th development phase (according to Feekes), respectively. Steady increase of the protein content in the ears was observed.
Highest peroxidase activity was found in the roots; it diminished from the onset of ontogenesis till maturity of the plants. In the leaves and stalks a slight decrease of peroxidase activity till the 10th development phase and then an increase till maturity was found. The ears exhibited a gradual increase of peroxidase activity. The course of specific peroxidase activity was found to be very similar to that of total activity.
Isoperoxidase patterns did not change significantly. In the leaves, a decrease of activity of C₄ and C₅ isoperoxidases was recorded. In the stalks, C l isoenzyme emerged at the end of ontogenesis. A gradual increase of A₁ and A₅ isoperoxidase intensity took place both in the leaves and stalks.

The morphoregulatory effect of FeEDTA chelating complex was verified in an androgenically more productive cultivar of tobacco White Burley and inDatura innoxia Mill. The presence of EDTA in Nitsch (1969) medium (N medium) was sufficient for the conversion of isolated embryoids and embryoids in anthers into complete plants. The androgenic development was most rapid in N medium with FeEDTA. In N medium with EDTA, the cultures developed more slowly and remained vital for a long time. In the medium without EDTA, new embryoids developed continuously. The embryoids arose and developed also in closed anthers. All embryoids which arose in anthers cultured on N medium were capable of forming complete plants. The threshold morphoregulatory concentration of FeEDTA was 40 μM FeEDTA per 1 litre of medium for embryoids in anthers and 30 μM FeEDTA per 1 litre for isolated embryoids. The dark brown colour of the anthers of tobacco andD. innoxia was due to the presence of iron (FeEDTA) in the culture medium. The morphoregulatory effect of EDTA in N medium is explained by the formation of a complex with iron present in the form of pollution of chemicals and agar. This amount of iron in complex with EDTA is sufficient for the conversion of embryoids into plants, but it is insufficient for the browning of anthers.

Different types of stress, such as hypersensitive reaction to viruses or necrotic response induced by chemical and mechanical injuries, caused similar patterns in early electrolyte leakage from discs of cowpea leaves. The electrolyte leakage, suggestive of permeability alterations, always occurred in advance of cell death. Altered permeability can therefore be considered as an aspecific response to stress and a marker of necrogenesis. No correlation was found between permeability alterations and the mechanism for virus localization, the main characteristic of the hypersensitive reaction, because tobacco rattle virus induced similar alterations in either incompatible cowpea or compatible tobacco plants. Early Ca²⁺ losses occurred following viral and abiotic necrogenic stresses. The external supply of Ca²⁺ to cowpea during the course of the hypersensitivity to viruses failed to effect pathogenesis, assessed as the number and size of the resulting necrotic local lesions, and the release of electrolyte leakage from the infected leaves. However, the external supply of Ca²⁺ counteracted the negative effect of EDTA, a chelating agent, on the resistance of cowpea leaves to cell-to-cell spread of viruses, suggesting that a Ca²⁺-deficiency may weaken the mechanism of defense of the cells against the localized viral infection.

Field trials on the effect of chlorocholinechloride (CCC) on rye plants of the cultivar Danae and of a selected population "WRS" proved that rye principally shows as reaction analogous to wheat. The CCC-induced decrease of stalk length is due to the reduction of elongation growth of the 4th internode. This shortening effect is mainly the result of decreased cell extension and, in the middle internode, additionally of inhibited cell division in longitudinal direction. The shape of internodes is changed under the influence of CCC. Walls of parenchyma cells of CCC-treated plants are thinner and those of sclerenchyma cells are thicker compared with cell walls of control plants.