The influence of kinetin and sucrose on (60%), Hill activity (about 3-fold), and "C-fixation from NaH"CO3 (about 20%). On the other hand, the presence of sucrose in the medium reduced the chlorophyll content by about 30% and "C-fixation from NaH"4CO3 in the soluble fraction by about 60%. A possible correlation between the influence of kinetin on sugar uptake and the effect of kinetin on "C-fixation from NaH"CO3 was discussed.
The effect of natural air temperature on the vegetative growth and alkaloidal yield of H. muticus L. was studied. The highest number of branches, diameter, fresh and dry weights of stem and roots occurred in September sowing at full‐flowering and fruiting stages. Relatively higher temperature in Sept. sowing favoured leaf growth (number, area and dry weight). Hyoscyamine yield in different organs of the plants sown in Sept., excessively exceeded all other sowings during flower budding and full‐flowering stages. Hyoscine yield was quantitatively very small as compared with that of hyoscyamine and even could not be detected in the leaves of winter sowings during full‐flowering stage.
Reduction of stalk length in winter and summer rye by Ethrel (2‐chloroethylphosphonic acid).
In pot experiments with winter and summer rye Ethrel (2‐chloroethylphosphonic acid) considerably reduced stalk length so that a favourable effect on lodging can be expected. The shortening effect strongly depends on the time of application. Grain yield is scarcely affected. The experiments give indication for the optimal concentration and the amount of active substance required.
The influence of isoosmotic Lutrol‐ and salt solutions upon the chlorophyll‐concentration and chlorophyll a/b ratio of Phaseolus vulgaris
The behaviour of the chlorophyll status of Phaseolus vulgaris was studied under the influence of different isoosmotic Lutrol and salt solutions in the root medium.
Phaseolus seedlings, 12 days old, were raised in a nutrient solution containing isoosmotic concentrations of 0.54 (control); 1.26; 2.82 and 4.68 atm. created by either Lutrol or salts (40% chlorine, 60% sulfate). An increase in the osmotic pressure of the primary and normal leaves generally paralleled the increase in the osmotic pressure of the media with a more pronounced effect in the case of salts than in Lutrol. Mean values of osmotic pressure of both primary and normal leaves during the sampling period were 6.19; 10.35 and 12.98 atm. for control, Lutrol III and salt III respectively.
Increasing the osmotic pressure of the media due to salts resulted in a significant decrease of the chlorophyll content of primary leaves (mean value during the sampling period: Cont.: 19.8 μg/cm2; salt II: 12.7 μ/cm2; salt III: 6.3 μg/cm2), accompanied with a decreasing tendency in the chlorophyll a/b ratio. Such effect was only detectable in the case of the highest Lutrol concentration at the end of the experiment. However, the mean values of the sampling period did not show any significant variation from those of controls (Lutrol II: 18.9 μg/cm2; Lutrol III: 16.1 μg/cm2). Both types of osmoticum decreased remarkably the total chlorophyll amount of normal leaves. This behaviour resulted more clearly from a reduction in the leaf area than from the decrease in the chlorophyll concentration.
The mechanism of plant response to changes in the osmotic pressure of the medium seemed to depend mainly on the type of osmoticum affecting such variations. In general the changes in the osmotic pressure created by salts affected both mature and developing leaves i.e. primary and normal leaves respectively, whereas such changes in the case of Lutrol affected mainly the latter organs.
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