Effects of salinity and benzyl adenine on development and function of microhairs of Zea mays L

Abstract

Bicellular microhairs are present on the surfaces of leaves of grasses with the exception of the Pooideae. In some halophytic grasses, these glandular hairs secrete salt, suggesting the intriguing question 'can the microhairs of grasses that do not normally encounter salinity also secrete salt?' Microhairs were counted in replicas of the adaxial and abaxial surfaces of leaves of various ages of maize plants growing either in the absence of salt or in the presence of 40, 80 or 120 mM NaCl. The number of microhairs per unit area of adaxial leaf surface of the youngest leaf almost doubled as the salinity increased from zero to 120 mM NaCl; on the abaxial surface, the number of microhairs increased by 50%. Spraying this leaf with benzyl adenine (BA) caused, when averaged across salinities and surfaces, a 32% increase in the number of microhairs. Salinity reduced leaf area but in all the salinity treatments, spraying with BA increased the total number of microhairs per leaf. Washing leaves of plants provided estimates of the loss of salt from those leaves. There were large differences between the Na:K molar ratios in the washing solution and the leaf tissue, indicating a high selectivity for sodium over potassium for loss from the leaf. BA did not influence the efficiency of salt loss, expressed per microhair, at any salinity level, but did increase loss per leaf. Thus, BA increased salt loss from plants due to its influence on the number of microhairs and leaf area, but not due to its effect on the efficiency of the secretion process per se.

6-Benzylaminopurine treatment induces increased pubescence on wheat leaves

“…2). These results are consistent with those for prickles of maize (Zea mays L.) with BA treatment and macrohairs of Rhodes grass (Chloris gayana Kunth) with MeJA treatment (Kobayashi et al 2010;Ramadan and Flowers 2004). An increase in trichome density in response to BA or jasmonates has been reported previously in dicotyledonous plants such as Arabidopsis, Artemisia annua and Lycopersicon esculentum (Boughton et al 2005;Maes et al 2008Maes et al , 2011Traw and Bergelson 2003).…”

“…In Arabidopsis, jasmonic acid (JA), a jasmonate, increases the size and density of trichomes, and 6-benzylaminopurine, a cytokinin, reduces trichome size but increases their density (Maes et al 2008). Since application of these two hormones increases trichome density in Poaceae plants (Kobayashi et al 2010;Ramadan and Flowers 2004), their application was also expected to affect trichome size for plants in the Poaceae, including wheat.…”

Comparison of the effects of NaCl and KCl at the roots on seedling growth, cell death and the size, frequency and secretion rate of salt glands in leaves of Limonium sinense

“…Rozema et al (1977) found increases in the number of salt glands in Glaux maritime as external salt concentrations increased, while Liphschitz et al (1974) found the number of glands in Chloris gayana unchanged by 5-day exposure to salt. However, sprays of the synthetic cytokinin benzyl adenine (BA) can increase the number of glands in Chloris guayana and in maize, BA treatment increased the loss of sodium (Ramadan and Flowers 2004). In maize, this increased Na ?…”

Evolution of halophytes: multiple origins of salt tolerance in land plants

“…glands that originally performed some other function is unclear, but it is difficult, at least in the Poaceae, to get glandular hairs on non-halophytes (such as Zea mays L.) to secrete salt (Ramadan and Flowers 2004).…”