Endogenous Abscisic Acid Promotes Hypocotyl Growth and Affects Endoreduplication during Dark-Induced Growth in Tomato (Solanum lycopersicum L.)

Abstract

Dark-induced growth (skotomorphogenesis) is primarily characterized by rapid elongation of the hypocotyl. We have studied the role of abscisic acid (ABA) during the development of young tomato (Solanum lycopersicum L.) seedlings. We observed that ABA deficiency caused a reduction in hypocotyl growth at the level of cell elongation and that the growth in ABA-deficient plants could be improved by treatment with exogenous ABA, through which the plants show a concentration dependent response. In addition, ABA accumulated in dark-grown tomato seedlings that grew rapidly, whereas seedlings grown under blue light exhibited low growth rates and accumulated less ABA. We demonstrated that ABA promotes DNA endoreduplication by enhancing the expression of the genes encoding inhibitors of cyclin-dependent kinases SlKRP1 and SlKRP3 and by reducing cytokinin levels. These data were supported by the expression analysis of the genes which encode enzymes involved in ABA and CK metabolism. Our results show that ABA is essential for the process of hypocotyl elongation and that appropriate control of the endogenous level of ABA is required in order to drive the growth of etiolated seedlings.

Spatio-temporal changes in endogenous abscisic acid contents during etiolated growth and photomorphogenesis in tomato seedlings

“…Indeed, LeNCED1 transcripts accumulated significantly in the D-grown seedlings than in de-etiolated seedlings. 5 Altogether, our previously published results demonstrated ABA accumulation is required to stimulate the fast growth of tomato hypocotyl during skotomorphogenesis.…”

“… 11 Interestingly, there was marked great accumulation of free ABA in the elongating zone of hypocotyl, further supporting our published data. 5 Finally, the low concentration of free ABA in the root throughout the experimental period indicated that ABA probably has no or only a limited role during early root development in tomato seedling. However, a potential effect of artificial in vitro cultivation especially in root development cannot be excluded.…”

“…We recently studied the role of ABA in the growth of etiolated tomato hypocotyls using ABA-deficient sitiens and notabilis mutants. 5 Physiological experiments showed a significant reduction in hypocotyl growth in the mutants compared to wild-types (WTs). Low concentrations of ABA (nM) stimulated the mutant growth but not the WTs.…”

Seed Hydropriming and Smoke Water Significantly Improve Low-Temperature Germination of Lupinus angustifolius L.

“…Although the level of ABA seems to play a key role in seed germination, a decrease in the endogenous ABA does not always correlate with germination [ 39 ] or is not sufficient to break dormancy in some dormant seeds [ 40 ]. Humplik et al [ 41 ] showed that ABA was essential for hypocotyl elongation and that appropriate control of the endogenous level of ABA was required in order to drive the growth of etiolated seedlings.…”

Arabidopsis Responds to Alternaria alternata Volatiles by Triggering Plastid Phosphoglucose Isomerase-Independent Mechanisms

“…The phenotyping system was equipped with a FluorCam unit for pulse amplitude-modulated measurement of chlorophyll fluorescence. After 20 min of dark adaptation, the standardized measurement protocol was applied, as described by Humplík et al (2015). The parameters F Po , F PSII , and F NPQ were calculated from the measured parameters according to Lazár (2015).…”