Stomatal density in quinoa

Genotypic difference in salinity tolerance in quinoa is determined by differential control of xylem Na⁺ loading and stomatal density

by Shabala S., Hariadi Y., Jacobsen S.-E. (2013)

in  J. Plant Physiol. 170, 906–914. doi: 10.1016/j.jplph.2013.01.014 – Pubmed Abstract | Pubmed Full Text | CrossRef Full Text | Google Scholar

Abstract

Quinoa is regarded as a highly salt tolerant halophyte crop, of great potential for cultivation on saline areas around the world. Fourteen quinoa genotypes of different geographical origin, differing in salinity tolerance, were grown under greenhouse conditions. Salinity treatment started on 10 day old seedlings. Six weeks after the treatment commenced, leaf sap Na and K content and osmolality, stomatal density, chlorophyll fluorescence characteristics, and xylem sap Na and K composition were measured.

Responses to salinity differed greatly among the varieties. All cultivars had substantially increased K⁺ concentrations in the leaf sap, but the most tolerant cultivars had lower xylem Na⁺ content at the time of sampling. Most tolerant cultivars had lowest leaf sap osmolality. All varieties reduced stomata density when grown under saline conditions. All varieties clustered into two groups (includers and excluders) depending on their strategy of handling Na⁺ under saline conditions. Under control (non-saline) conditions, a strong positive correlation was observed between salinity tolerance and plants ability to accumulate Na⁺ in the shoot. Increased leaf sap K⁺, controlled Na⁺loading to the xylem, and reduced stomata density are important physiological traits contributing to genotypic differences in salinity tolerance in quinoa, a halophyte species from Chenopodium family.

See the text: ScienceDirect

Stomatal behavior and traits

 

Linking stomatal traits and expression of slow anion channel genes HvSLAH1 and HvSLAC1 with grain yield for increasing salinity tolerance in barley

by Liu X., Mak M., Babla M., Wang F., Chen G., Veljanoski F., Wang G., Shabala S., Zhou M., Chen Z.-H. (2014)

in Front. Plant Sci.,5: 634, 25 November 2014 | http://dx.doi.org/10.3389/fpls.2014.00634

Soil salinity is an environmental and agricultural problem in many parts of the world. One of the keys to breeding barley for adaptation to salinity lies in a better understanding of the genetic control of stomatal regulation.

We have employed a range of physiological (stomata assay, gas exchange, phylogenetic analysis, QTL analysis), and molecular techniques (RT-PCR and qPCR) to investigate stomatal behavior and genotypic variation in barley cultivars and a genetic population in four experimental trials.

A set of relatively efficient and reliable methods were developed for the characterization of stomatal behavior of a large number of varieties and genetic lines. Furthermore, we found a large genetic variation of gas exchange and stomatal traits in barley in response to salinity stress. Salt-tolerant cultivar CM72 showed significantly larger stomatal aperture under 200 mM NaCl treatment than that of salt-sensitive cultivar Gairdner.

Stomatal traits such as aperture width/length were found to significantly correlate with grain yield under salt treatment. Phenotypic characterization and QTL analysis of a segregating double haploid population of the CM72/Gairdner resulted in the identification of significant stomatal traits-related QTLs for salt tolerance. Moreover, expression analysis of the slow anion channel genes HvSLAH1 and HvSLAC1 demonstrated that their up-regulation is linked to higher barley grain yield in the field.

Read the full article: Frontiers in Plant Science

Stomatal characteristics, tissue ion relations, and salinity tolerance

 

Linking osmotic adjustment and stomatal characteristics with salinity stress tolerance in contrasting barley accessions

by Zhu M., Zhou M., Shabala L., Shabala S. (2015)

in Functional Plant Biology, 42, (3) pp. 252-263. ISSN 1445-4408 (2015)

Abstract

Salinity tolerance is a complex trait – both physiologically and genetically – and the issue of which mechanism or trait has bigger contribution towards the overall plant performance is still hotly discussed in the literature.

In this work, a broad range of barley (Hordeum vulgare L. and Hordeum spontaneum L.) genotypes contrasting in salinity stress tolerance were used to investigate the causal link between plant stomatal characteristics, tissue ion relations, and salinity tolerance. In total, 46 genotypes (including two wild barleys) were grown under glasshouse conditions and exposed to moderate salinity stress (200 mM NaCl) for 5 weeks. The overall salinity tolerance correlated positively with stomata density, leaf K⁺ concentration and the relative contribution of inorganic ions towards osmotic adjustment in the shoot. At the same time, no correlation between salinity tolerance and stomatal conductance or leaf Na⁺ content in the shoot was found. Taken together, these results indicate the importance of increasing stomata density as an adaptive tool to optimise efficiency of CO₂ assimilation under moderate saline conditions, as well as benefits of the predominant use of inorganic osmolytes for osmotic adjustment in barley. Another finding of note was that wild barleys showed rather different strategies dealing with salinity, as compared with cultivated varieties.

See the text: UTAS