Effect of brassinolide

Table I. Effect of brassinolide, homobrassinolidea and IAA on the lamina inclination of rice seedlings...

Effects of Brassinolide on Elongating Soybean Stem Sections... 

Figure 1. Effect of Brassinolide on Elongation of Soybean and Arabidopsis thaliana stem sections. Epicotyl sections (1.5 cm, soybean) or peduncle sections (1 cm, Arabidopsis) were excised and treated as described in the text. EE + BR = 25 nM BR, elongating epicotyl EE - BR = elongating epicotyl control BE + BR = 25 nM BR, basal epicotyl BE - BR = basal epicotyl control. A = 250 nM BR, peduncle B = 25 nM BR, peduncle C = control peduncle.

Figure 6. Effect of Brassinolide on Xylem Differentiation in Helianthus tuberosus. Explants were harvested 24, 48 or 72 hours after incubation on xylogenic medium (23) with (open bars) or without (closed bars) 68 nM BR.

Effects of Brassinolide on Growth and Chilling Resistance of Maize Seedlings... 

Effect of brassinolide on greening of etiolated maize seedlings under light... 

Effect of brassinolide on growth recovery of maize seedlings after chilling... 

The effects of brassinolide were similar in the light and in the dark, but the coleoptile and mesocotyl were elongated more and leaf growth was retarded more in the dark than in the light by brassinolide at 10° ppm. These results were in sharp contrast to those experimental results obtained with Avena coleoptiles (5) and with soybean and mung bean tissues (i, 6). 

Figure 2. Effects of brassinolide on the growth of organs in maize seedlings.

Effect of Brassinolide on Greening of Etiolated Maize Seedlings under Light... 

It has been reported (8-12) that brassinolide increases the chlorophyll content of several crops in the field, but the effect of brassinolide on the... 

Effect of Brassinolide on Growth Recovery of Maize Seedlings after Chilling Stress... 

The three experiments with brassinolide showed that the physiological effect of brassinolide seems to be that of both an auxin and cytokinin. The twining growth effect, however, is the characteristic response evoked by brassi-nosteroids, and it was thought that the twining movement of the tendril and the twiner (climber) reported for auxin, or abscisic acid (ABA), or ethylene earlier is doubtful. In other words, brassinolide as a steroid may act on membrane systems. 

Figure 1. Effect of brassinolide on the growth (A) and cotyledon-chlorophyll content (B) of cucumber seedlings subjected to chilling stress, measured 5 days after chiding treatment. (Ochi, N. and Katsumi, M. unpublished)...

Figure 5. Effects of Brassinolide and IAA on proton secretion from peeled hypocotyl sections.

Effects of Brassinolide on Conditioning and Germination of Witchweed (Striga asiatica)... 

The mechanism of action of brassinolide is still unknown therefore studies should be conducted further to understand the physiological effects of brassinolide on conditioning and germination of witchweed seeds. 

Brassinolide increased the grain weight and the percentage of ripened grains in rice plants. Brassinolide treatment promoted assimilation of - C in leaf blades and successive translocation of the radioactive assimilate into panicles. Accumulation of starch in panicles was enhanced by brassinolide treatment. The effect of brassinolide on the ripening of rice plants may be attributed to the enhancement of the synthesis and translocation of photosynthetic products. 

Table I. Effect of Brassinolide on Weight of Grain in Rice Plants (cv.Nipponbare) under (A) Greenhouse and (B) Phytotron(20°C/13°C) Conditions...

Figure 1. Effect of Brassinolide on Starch Content in Leaf Sheath of Rice Plants.

Table II. Effect of Brassinolide on IAA and ABA Levels in Grains under Greenhouse and Phytotron (22°C/17°C) Conditions...

Effect of Brassinolide on Levels of Indoleacetic Acid and Abscisic Acid in Squash Hypocotyls... 

Recently brassinolide was found to retard the abscission of leaf explants of Calamondin (6). Thus, the present experiments were also included to observe the effects of brassinolide on the fruit set of Morita navel oranges (Citrus sinensis), a cultivar derived from Washington navel. 

The experiments after the cessation of "June drop" were also counted. However, after that period, only 5% of abortion was seen even in the control trees. Thus, it was difficult to show a stimulating effect of brassinolide in this treatment. 

There is further evidence to support the claim that brassinosteroids are hormonal in their action (6). These are the effects of brassinolide on gravitropism (7), effects in conjunction with light quality (8), effects on photosynthate partitioning (9), probable effects on phytochrome (10), substitution for indole-3-acetic acid in soybean epicotyls (11), enhancement of xylem differentiation (11), stimulation of membrane permeability in cucumber hypocotyls (12), and stimulation of ATPase activity (12). Taken objectively, many of these specific physiological and biochemical functions which are attributed to brassinolide, and by inference to the brassinosteroids in general, have been attributed to the other plant hormones, especially indole-3-acetic acid and the gibberellins (6, 13). 

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