Premium
Sodium chloride stress induces nitric oxide accumulation in root tips and oil body surface accompanying slower oleosin degradation in sunflower seedlings
Author(s) -
David Anisha,
Yadav Sunita,
Bhatla Satish C.
Publication year - 2010
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2010.01408.x
Subject(s) - oleosin , helianthus annuus , seedling , sunflower , chemistry , nitric oxide , endogeny , sodium , biochemistry , apoplast , biophysics , horticulture , biology , cell wall , organic chemistry , gene
Present work highlights the involvement of endogenous nitric oxide (NO) in sodium chloride (NaCl)‐induced biochemical regulation of seedling growth in sunflower ( Helianthus annuus L., cv. Morden). The growth response is dependent on NaCl concentration to which seedlings are exposed, they being tolerant to 40 m M NaCl and showing a reduction in extension growth at 120 m M NaCl. NaCl sensitivity of sunflower seedlings accompanies a fourfold increase in Na + /K + ratio in roots (as compared to that in cotyledons) and rapid transport of Na + to the cotyledons, thereby enhancing Na + /K + ratio in cotyledons as well. A transient increase in endogenous NO content, primarily contributed by putative NOS activity in roots of 4‐day‐old seedlings subjected to NaCl stress and the relative reduction in Na + /K + ratio after 4 days, indicates that NO regulates Na + accumulation, probably by affecting the associated transporter proteins. Root tips exhibit an early and transient enhanced expression of 4,5‐diaminofluorescein diacetate (DAF‐2DA) positive NO signal in the presence of 120 m M NaCl. Oil bodies from 2‐day‐old seedling cotyledons exhibit enhanced localization of NO signal in response to 120 m M NaCl treatment, coinciding with a greater retention of the principal oil body membrane proteins, i.e. oleosins. Abolition of DAF positive fluorescence by the application of specific NO scavenger [2‐phenyl‐4,4,5,5‐tetramethyllimidazoline‐1‐oxyl‐3‐oxide (PTIO)] authenticates the presence of endogenous NO. These novel findings provide evidence for a possible protective role of NO during proteolytic degradation of oleosins prior to/accompanying lipolysis.