Diverse effects of uniconazole and nicotinamide on germination, growth, endogenous hormones and some enzymic activities of peas

Pea seeds were soaked in different solutions of uniconazole or nicotinamide for 24 hours. The effects of such treatment on germination of these seeds and some growth parameters of the given plants concomitant with the changes in the hormonal contents and activities of IAA oxidase, amylase and proteinase were investigated. Uniconazole was found to retard the rate germination of the seeds and retard the elongation of stems accompanied with increases in the number of their lateral branches and stem thickness, but decreases the number of leaves and their area per plant leading to reduction in both fresh and dry weights of shoots and roots. These aspects were accompanied with clear reduction in the contents and levels of cytokinins, ABA and activity of IAA oxidase. In the same time the activities of amylase and proteinase were reduced. All these physiological phenomena were proportional to the concentration of uniconazole. On the other hand, nicotinamide caused diverse effects on the previously mentioned physiological phenomena as compared with those caused by the corresponding concentrations of uniconazole. This was accompanied by regular picture of hormone contents and complete disappearance of ABA, and these effects were proportional to nicotinamide concentrations. In all cases the endogenous hormonal picture coordinated with the different physiological changes studied

Growth, apical dominance and endogenous hormonal picture of normal, covered and decapitated duranta shoots

The effect of decapitation or covering the shoot apex on growth and endogenous hormonal picture of Duranta repens were studied. It was found that, the decapitated shoots do not increase in length, but carry more lateral branches leading to lowest apical dominance. This was accompanied by the least contents and levels of gibberellins and auxins with the appearance of ABA and highest content and levels of cytokinins. But, the length of intact shoots with exposed apical buds was highly increased with no laterals leading to highest apical dominance accompanied with a hormonal picture opposite to that found in the decapitated shoots. However, the branches with covered apices showed median patterns in growth, apical dominance and endogenous hormonal picture

Effect of mode application of some growth regulators on the physiology of tomato plants I effect of indole-acetic acid [IAA] on morphology, growth, metabolism and productivity

In the present study spraying the vegetative parts of tomato plants or root exposure to the different concentration of IAA [10, 20, 40, 80 ppm] gave evidence that IAA can be absorbed and translocated from the rooting media to the shoots and vice-versa. The length of the main stem of treated plants was maximum when 80 ppm IAA concentration was used accompanied by minimum lengths of the corresponding main roots. The changes in total carbohydrates was mainly in polysaccharide fractions, while those of the total nitrogen were mainly in proteins and nucleic acids mainly RNA, 10 ppm concentration was the most promotive but 80 ppm was the least promotive. IAA activated the intake of some mineral elements studied; the maximum increase was shown by 10 ppm which then decreases by the increase of IAA concentrations. IAA induced flower and fruit giving in number and weight and the greatest induction was noticed with 10 ppm concentration whether the plants were sprayed once or twice

Effect of mode of application of some growth regulators on the physiology of tomato plants: I effect of IAA on the endogenous hormonal contents

Application of 10 ppm IAA concentrations to the culture media or used as foliar spray of tomato plants caused stimulatory effects on growth, differentiation, development and fruiting of plants. 40 ppm concentration however, caused less activation than that exerted by 10 ppm concentration. This was accompanied with regular increases in the contents and levels of auxins, gibberellins and cytokinins leading to hormonal balance. The high concentration of IAA [80 ppm] however induced inhibiting effect on the previously mentioned phenomena which were accompanied with increases in the level and activity of endogenous inhibitors mainly unsaturated lactones and also with low levels of auxins, gibberellins and cytokinins leading to hormonal imbalance. Also the IAA oxidase activity was enhanced by the application of higher concentration of IAA. These results can easily interpret the previously mentioned results in the first paper of this series

Effect of mode of application of some growth regulators on the physiology of tomato plants III effect of nicotinamide on morphology, growth, metabolism and productivity

The present results showed evidence that nicotinamide is absorbed and translocated from the roots to the shoots and vice-versa. The length of the main stem and root as well as their lateral branches was increased by the increase of nicotinamide concentrations applied. This led to parallel increases in fresh and dry weights of the plant organs. The apical dominance of plants sprayed with 80 ppm nicotinamide was less than that of those sprayed with 10 ppm concentration. However, plants sprayed twice were more responsive than those sprayed once. Carbohydrates mainly polysaccharides, nitrogenous compounds mainly proteins, nucleic acids and uptake of some mineral elements-were increased by the increase of nicotinamide concentrations applied. Nicotinamide induces flowering and fruit growth in number and weight of fruits consequent to spraying mainly with 80 ppm concentrations

Effect of mode of application of some growth regulators on the physiology of tomato plants: IV-effect of nicotinamide on the endogenous hormonal contents

Application of 10, 40 and 80 ppm nicotinamide either to culture media or used as foliar spray of tomato plants caused stimulatory effects on growth, development, differentiation and fruiting of plants in the order 80 > 40 > 10 ppm, as already mentioned in paper 3 offered simultaneously by the same authors to the same journal. This was accompanied with regular increases in the contents and levels of auxins, gibberellins and cytokinins leading to hormonal balance. However, the IAA oxidase activity was progressively reduced by the increase in the concentration of nicotinamide used. These results safely coordinate with the previously mentioned results in the third paper of this series

Causes of blackening of infected spots of tomato fruits

Fruits of tomato infected with some pathogens especially Alternaria lycopersici showed substantial increases in levels of the aromatic amino-acids alpha amino butyric acid, tryptophane, tyrosine and phenylalanine when compared with the respective amino acids in the healthy plants of the same fruits. Also, total phenolic compounds and simple phenolic fractions namely: salicylic acid, orcinol, gallic acid and syringic acid as well as indole acetic acid and indole acetonitrile were increased in the infected tissue. Blackening of the infected spots was connected with the substantial increases of these compounds, the formation and transformation of which are responsive to the invading pathogens and to resist the resulting diseases