The effect of gibberellic acid and benzyl adenine on vegetative growth and changes in plant photosynthetic pigments of false Aralia, Schefflera and Benjamin's Ficus under irrigation conditions.

Academic Thesis for Master's Degree in Horticulture, Cultivation and Physiology of Ornamental Plants

Abstract

One ??of the characteristics of ornamental plants is the production of enough leaves and side branches to create a dense appearance. In some cases, it is necessary to treat non-branching cultivars with growth regulators to produce enough leaves and side shoots to achieve the above goal (dense appearance of the plant). The most widely used branching agents are benzyl adenine and gibberellic acid, both of which are plant growth regulators that cause the production of branches and leaves in plants. In this research, in the conditions of greenhouses under the mist irrigation system, gibberellic acid and benzyl adenine hormones were investigated on the ornamental leaf plants of Ficus benjamin, Schefflera and false Aralia under foliar spraying. Gibberellic acid and benzyl adenine at the levels of 0, 100 and 200 mg/liter were applied by foliar spraying during three stages with time intervals of 15 days. This experiment was done in factorial form in a completely randomized design with four replications. The effects of gibberellic acid and benzyladenine hormones at the level of 200 mg/liter were effective on the number of leaves and plant height. The highest amount of photosynthetic pigments in ornamental leaves of Ficus benjamin, Schefflera and Aralia plants was obtained at the combined level of 200 mg/l of gibberellic acid and benzyladenine. The highest amount of soluble carbohydrates in ornamental leaves of Ficus benjamin, Schefflera, and false Aralia were obtained at the level of 200 mg/L gibberellic acid, 200 mg/L gibberellic acid + 100 mg/L benzyladenine, and 200 mg/L gibberellic acid + 100 mg/L benzyladenine, respectively. The highest amount of reducing sugar in the three ornamental leaves of Ficus Benjamin, Schefflera and Aralia false was related to the treatments of 200 mg/liter and the control with an average of 31.17, 57.58 and 40.28%, respectively. According to the obtained results, the highest amount of reducing sugar in the three investigated plants was related to Ficus Benjamin, which was higher than the other two ornamental leaf plants. The results of this research showed that the combined concentrations of 200 mg/L of the growth regulators gibberellic acid and benzyladenine significantly increased the rate of morphological growth, acceleration of chlorophyll and carotenoid synthesis, and the amount of reducing sugar and soluble carbohydrates in the ornamental leaves of Aralia false, Schefflera and Ficus Benjamin.

keywords: plant growth regulators, leaf area, reducing sugars, soluble carbohydrates, ornamental leaf plants, leaf chlorophyll content.

discovery of plant growth substances

1-1-1 gibberellins

in the presence of growth inhibitory substance Fusaric acid (5-n-butyl picolinic acid) is prevented in the stage of refining and purifying the produced substance of Bacana. However, in 1935, Yabuna isolated active crystalline substances from purified sterile culture medium of Gibberella fujikuri (Yabuna, 1935). When this substance was used in the roots of rice seedlings, it stimulated its growth and was named gibberellin A. This was the first time that the term Gibberellin was used in scientific sources. Yabata and Simiki (1983) were successful in crystallizing gibberellin A and gibberellin B, but due to the war, the study on gibberellin was abandoned. In the 1950s, British, American, and Japanese scientists focused on the growth-regulating properties of gibberellic acid and identified gibberellin in mushroom extracts, and they finally discovered this compound in higher plants. In 1954, British researchers (Bryan et al., 1954) identified the plant growth regulating properties of gibberellic acid in the product obtained from the mushroom Gibberella fujikuroi. In 1955, American scientists (Stola et al., 1955) identified gibberellin A or gibberellin X from the purified and sterile culture medium of Gibberella fujikuri. Also, in 1955, Japanese scientists (Takahishi et al., 1955) found that gibberellin A contains three distinct compounds, which they named It is now generally agreed that gibberellin X is gibberellic acid and similar compounds. In fact, today gibberellic acid and GA3 are synonymous.During 1956, Radley identified substances similar to gibberellic acid in plants, and since then gibberellins have been shown to be a widespread general substance in higher plants (Takahashi et al., 1991). It was discovered in 1955 but there is no parallel for either. McMillan and Takahashi (1968) considered specific numbers from Gibberellin to regardless of their origin. This method is used today for more than 90 known and common types of gibberellins. He said that the substances secreted from the flushing vessel can stimulate cell proliferation in potato tuber tissues. Almost a year later, Van Auerbeek et al. (1914) showed that naturally occurring substances in coconut sap (liquid endosperm) have the ability to accelerate cell proliferation in fresh Datura embryos. Van Orbeek et al. (1944) reported that the extract of Tatura embryo, yeast, wheat germ and almond powder accelerated the cell division in Tatura embryo culture media and then showed that these substances have the necessary extent of action. Haberlent's research was developed by Jablonski and Slog in 1954, who showed that vascular tissue cells contain substances that stimulate cell division in tobacco plants. In 1955, Miller et al. were the first to report the isolation and purification of kinetin (6-furfurylaminopurine), which was obtained from DNA contained in old, autoclaved herring sperm, and they called this compound kinetin. Because this substance had the ability to accelerate cell division with cytokines in tobacco brain tissue (Miller et al., 1955). Hall and Droop (1955) showed that kinetin can be produced by autoclaving a mixture of adenine and furfurylamine and then showed that kinetin can be obtained from the breakdown of DNA products. In 1961, Miller reported the identification of a natural quintin-like compound in corn, which was later named zeatin. Latham (1963) described the effect of zatin as a stimulating agent for cell division in corn and later described the chemical properties of this substance (Latham, 1964). In another experiment, Shaw and Wilson (1964) identified the structure of zatin and showed that this substance was not a synthetic compound. After classifying the available sources in this field, they attributed the discovery of Zaatin to Latham and Miller (1963). Since the discovery of zaatin, numerous additional cytokinins have been found and are found throughout the plant kingdom.

1-2 Summary of plant growth regulator gibberellins and cytokinins

1-2-1 Gibberellins

Gibberellins They are a group of plant growth materials that structurally have a gibberellin skeleton (Figure 1-a). These substances stimulate cell division and cell elongation, and their other regulatory actions are carried out in a manner similar to gibberellic acid.

GA3 was the first commercially available gibberellin. Historically, this compound has been called gibberellic acid, and it has been used as a standard indicator in bioassay systems, and for this reason, the structural formula of this compound represents more than 90 types of gibberellins known today. rtl;">An important characteristic of foliage plant cultivars is the production of enough lateral or basal shoots to give a full and compact appearance. In some cases it may be necessary to treat non-branching cultivars with growth regulators that induce lateral or basal shoot development to achieve this result. The most commonly used branching-inducers are gibberellic acid (GA3) and N6-benzyladenine (BA) which are synthetic cytokinins that have been shown to increase shoot number in a number of plant species.