Читать книгу Nitric Oxide in Plants - Группа авторов - Страница 26

NO has been shown to play an important role in the modulation of various physiological processes of plants mentioned in Table 2.1. Some of those processes include germination of seed and pollen, plant growth and development, closing and opening of stomata, senescence, flower development, and fruit ripening (Kopyra 2004; Delledonne 2005; Wilson et al. 2008). NO was documented to induce germination in light-dependent Arabidopsis and lettuce seeds, which indicates that NO takes part in root development (Li et al. 2016). Various NO donors stimulated root tip enlargement of Zea mays, in a dosage-related mode, and its length was prohibited by a NO scavenger (methylene blue) (Kopyra 2004). It has been proposed that NO and indole-3-acetic acid share some common steps in cell signaling, as they both stimulate the same plant response. Various studies have been suggested that stress regulates the endogenous levels of indole-3-acetic acid. As well as root growth and development, NO was found to be involved in the development and realignment of pollen tubes, best studied in A. thaliana (Pagnussat et al. 2003, 2004). It has been reported that NO has also been involved in the synthesis of several biological constituents including saponin and phytoalexin (Pagnussat et al. 2003, 2004).

Table 2.1 Role of nitric oxide (NO) during abiotic stress.

Abiotic stress	NO-mediated effect	Plant species	Reference
Drought	Abscisic acid signaling and closure of stomata	Pisum sativum	Syed Nabi et al. 2019
Salt	Increased tolerance of root growth	Oryza sativaNicotiana tabacum	van Zelm et al. 2020
Heavy metals	Heightened response in terms of root growth and oxidative stress	LupinusChlorella vulgaris	Solórzano et al. 2020
Temperature	Release of NO and increased tolerance of seedlings	Oryza sativaNicotiana tabacum	Syed Nabi et al. 2019
Ultraviolet radiation	Nitric oxide synthase activity	Arabidopsis thaliana	Tossi et al. 2009

Plants have established multifaceted innate/induced and hypersensitive mechanisms (HR) to protect themselves from pathogenic microorganisms, which subsequently terminate in systemic acquired resistance (SAR). An initial significant event is the elevation of Ca²⁺by using the plasma membrane cyclic nucleotide-gated ion channels (CNGCs). This is consistent with a role for cyclic guanosine monophosphate (cGMP) in plants, and various putative guanylate cyclase activity proteins including phytosulfokine receptor (PSKR). In PSKR, the cytosolic guanylate cyclase domain is activated by its biologically active ligand, a sulfonated phytosulfokine. An increase in Ca²⁺triggers the creation of SA, NO, and reactive oxygen species (ROS), which stimulates apoptosis in the proximity of the infection, thereby restraining pathogen progression (Heath 2000; Mur et al. 2019; Noman et al. 2020).