Effects of root applications of gibberellic acid on photosynthesis and growth in C3 and C4 plants

Abstract

The effects of root applications of gibberellic acid (GA3) on growth and photosynthesis of 12 species of plants including C3 monocots (Triticum aestivum L., wheat, Hordeum vulgare L., barley and Avena sativa L., oat), C3 dicots (Vigna radiata L., mung bean, Cucurbita moschata L., squash and Capsicum annuum L., pepper), C4 monocots (Zea mays L., corn, Sorghum vulgare L., sorghum and Panicum ramosum L., millet) and C4 dicots (Amaranthus retroflexus L., pigweed, Kochia scoparis L., kochia and Gomphrena celosoides L., gomphrena) were evaluated. Relative growth rates (RGR) of barley, oat, squash, pepper, corn, sorghum, millet, pigweed and kochia were increased above the control by 12.7%, 9.9%, 11.3%, 10.7%, 19.2% 10.1%, 11.5%, 16.4% and 32.7% respectively, four days following optimum GA3 treatments. There was no effect of GA3 on RGR in wheat, mung bean, and gomphrena. Gibberellic acid decreased the chlorophyll content expressed on an area basis by 20.0%, 13.9%, 20.9%, 17.1%, 11.9% and 28.0% in barley, squash, pepper, sorghum, pigweed and kochia, respectively, while that of oat, wheat, mung bean, corn, millet and gomphrena remained unchanged. When photosynthetic rates were expressed per mg of chlorophyll, it showed that GA3 could stimulate photosynthesis in barley, squash, pepper, sorghum, millet, pigweed and kochia by 20.4%, 20.6%, 16.5%, 17.4%, 10.4%, 24.2%, and 29.4%; while there was no effect in oat, wheat, mung bean, corn and gomphrena. An increase in leaf blade area and/or length of sheath were observed in GA3 treated plants of oat, barley, mung bean, squash, pepper, corn, sorghum, millet and kochia. The transpiration rate remained unchanged following GA3 treatment in all 12 species.

Effects of Nano Silver Particles and Gibberellic Acid on Growth and Some Physiological Characteristics of Dalbergia Sissoo Roxb.

“…Even though, the same results discovered by Mazumdar (2014) and Singh & Kashyap (2015). The results of chlorophyll content treated by gibberellic acid agreed with Tsai & Arteca (1985) and Stirk et al (2019). The lower concentrations of NS and GA3 treatments had significant effect on increasing shoot total carbohydrate compared to other treatments.…”

Expression of ZmGA20ox cDNA alters plant morphology and increases biomass production of switchgrass (Panicum virgatum L.)

“…Biomass improvement by modulation of GA20ox genes has been achieved in some dicot plants such as tobacco and hybrid aspen (Biemelt et al ., ; Eriksson et al ., ). In this study, the observed alteration of plant architecture of transgenic switchgrass with the ZmGA20ox gene under the control of the CaMV35S promoter resembled that in dicots (Biemelt et al ., ; Carrera et al ., ; Croker et al ., ; García‐Hurtado et al ., ), maize (Voorend et al ., ) as well as that of exogenous applications of GA 3 to other monocots (Tsai and Arteca, ). These architecture changes included longer leaves, internodes and tillers but smaller leaves and internode diameters compared to wild‐type control plants.…”

Detection of ancient maize in lowland Maya soils using stable carbon isotopes: evidence from Caracol, Belize

“…Maize is the only C 4 plant known to be cultivated in this area [57,87,93]. Other crops grown by the ancient Maya, such as Phaseolus vulgaris L. [31], Cucurbita moschata [88], Capsicum annuum [88], Manihot esculenta [16], Gossypium hirsutum [26], Ipomoea batatas [44], Persea americana [32], Theobroma cacao [26], Anacardium occidentale [4], Psidium guajava [73], Carica papaya [51], and Celtis sp. [53], have been identified as C 3 plants.…”