Effects of plant growth regulators on growth, flowering, fruiting and fruit yield of cucumber (Cucumis sativus L.): A review

Abstract

This review provides a comprehensive overview of the basic and applied aspects of different plant growth regulators in the regulation of growth and development of cucumber plants. The study is completely based on the use of secondary sources of data; related journals, government institutes, and relevant reports. Foliar application of PGRs has been shown to change the physiological and developmental processes, including plant vegetative growth, sex expression, yield, and yield components in cucumber. There are basically two types of growth regulators; plant growth promoters such as auxin, gibberellins, cytokinins, maleic hydrazide, ethephon, etc. and plant growth inhibitors such as ethylene, abscisic acids, dormins, etc. The combined use of auxins and gibberellins result in increased secondary growth. Maleic hydrazide (MH) along with Ethephon at 100 ppm each increases the number of nodes and primary branches. Ethrel at 300-400 ppm retards the secondary development and increase femaleness, and at 200-300 ppm make fruit surface smooth. Silver nitrate (AgNO3) at 400 ppm enhances the maleness in cucumber. Application of Ethephon at 300 ppm reduces the harvesting time of the fruit. Salicylic acid (at 2 doses of 0.07 mm/l + 0.18 mm/l) increases chlorophyll content and its exogenous application increases the fruit yield. Maleic Hydrazide (MH) alone at 100 ppm increases the femaleness, inhibits apical growth at 50-100 ppm, and increases fruit size at 200 ppm. Therefore, various auxin [indole-3-acetic acid (IAA), NAA], auxin transport inhibitor (TIBA), cytokinins (KIN), gibberellin [gibberellic acid (GA3)], ABA, ethylene [(2-chloroethylphosphonic acid (ethrel; ethephon; CEPA)] and growth retardant (MH) have been applied to control the vegetative growth and to maximize yield of cucumber. Numerous obstacles have hindered the quality cucumber production in Nepal; like environmental stresses, biotic and abiotic constraints, pest and disease outbreaks, and many others. The use of exogenous plant growth regulators has been crucial to Nepali cucumber producers as plant growth regulators has hasty effect on vegetative as well as the quality yield of plants. This study aims to reveal the suitable concentrations for the applications of growth regulators so that the use of such regulators is environmentally and toxicologically safe for both plants and the consumers.

Variation in Shoot, Peduncle and Fruit Growth of Lagenaria siceraria Landraces

“…In pedunculated cucurbits such as Cucumis sativus , fruit growth is attained through cell expansion and progressive maturation until ripening, which resembles a sigmoid growth habit [ 44 , 45 , 46 ]. Fruit cell number and size are key limiting factors in determining the fruit size and shape, whereby fruit growth is maintained by an accelerated cell division from 0 to 6 DAA, and, thereafter, an exponential enlargement stage from 6 to 15 DAA [ 45 , 47 ].…”

“…Fruit cell number and size are key limiting factors in determining the fruit size and shape, whereby fruit growth is maintained by an accelerated cell division from 0 to 6 DAA, and, thereafter, an exponential enlargement stage from 6 to 15 DAA [ 45 , 47 ]. Such growth and enlargement are largely controlled by phytohormones such as auxin, gibberellins, cytokinins, abscisic acid and ethylene [ 46 ]. Before anthesis, fruit shape and size are correlated with the shape and size of developing inferior ovaries [ 48 , 49 ].…”

“…Before anthesis, fruit shape and size are correlated with the shape and size of developing inferior ovaries [ 48 , 49 ]. A related study on C. sativus recorded an increase in the ovary size pre-anthesis, arguably due to the presence of endogenous phytohormones in the ovules as early as six days before anthesis (DBA) [ 46 , 48 ]. This phenomenon drives the orientation and magnitude of cellular division, subsequently impacting the fruit shape and size of cucurbits [ 47 ].…”

The Effect of Foliar Application with Naphthalene Acetic Acid and Potassium Nitrate on the Growth, Sex Ratio, and Productivity of Cucumbers (Cucumis sativas L.) under High Temperatures in Semi-Arid Areas

“…Plant growth regulators are among the most important chemicals that affect the flowering time and sex of plants [20,57,58]. The use of naphthalene acetic acid led to a minimum sex ratio, which led to an increase in the female functional organ [59][60][61]. Some studies reported that the increase in cucumber productivity is due to the positive role of NAA, which significantly reduced staminate flowers and increased pistillate flowers in cucumbers [28,60,62,63].…”

Effect of Different Growth Regulators on Plant Growth and Yield of Bottle Gourd (Lagenaria siceraria L.) cv. Arka Bahar

“…Similar results also reported by Sidhu et al [12 in Muskmelon and Node number of first female flower Similar results also reported by Chowdhary et al [13] in bottle gourd. Sanjeevan Gosai et al [14] observed that Ethrel was found effective in decreasing the number of male or staminate flowers per vine. Similar results were also observed by Ghani et al [15] in bitter gourd (Momordica charantia).…”