Hydraulic and chemical signalling in the regulation of stomatal conductance

 

Photo credit: Google

Vitis vinifera

Hydraulic and chemical signalling in the regulation of stomatal conductance and plant water use in field grapevines growing under deficit irrigation

by Rodrigues M.L., Santos T.P., Rodrigues A.P., de Souza C.R., Lopes C.M., Maroco J.P., Pereira J.S., Chaves M.M. (2008)

M. Lucília Rodrigues A D , Tiago P. Santos A , Ana P. Rodrigues A B , Claudia R. de Souza B , Carlos M. Lopes A , João P. Maroco B C , João S. Pereira A, M. Manuela Chaves A B

A Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal.

B Laboratório de Ecofisiologia Molecular, Instituto de Tecnologia Química e Biológica, Apartado 127, 2780-901 Oeiras, Portugal.

C Instituto Superior de Psicologia Aplicada. Rua Jardim do Tabaco, 34, 1149-047 Lisboa, Portugal.

 

in Funct. Plant Biol. 35: 565–579 – https://doi.org/10.1071/FP08004 –

Google Scholar CrossRef

http://www.publish.csiro.au/fp/FP08004

Abstract

Effects of irrigation strategies on stomata and plant water use were studied in field-grown grapevines (Vitis vinifera L.).

We assessed the importance of root-derived chemical signals vs. hydraulic signalling in stomatal regulation. The experiment included two treatments with the same water added to the soil (50% ETc) applied either to the whole root system (DI) or to half of the roots, alternating irrigation side every 15 days (PRD). Well-watered plants (FI) (100% ETc) and non-irrigated grapevines (NI) were also studied.

Partial stomata closure occurred in both PRD and DI plants. [ABA] of xylem sap remained constant during the day and was maintained throughout the season, with higher values in NI plants. Xylem sap pH was not affected by soil water availability.

A positive correlation between ψpd and maximum g s was found, indicating that grapevine stomata strongly respond to plant water status.

In contrast, ABA did not explain stomatal control at veraison. At mid-ripening g s was significantly correlated with ABA, apparently interacting with the rise in xylem sap pH.

Therefore, our data suggest that hydraulic feedback and feed-forward root-to-shoot chemical signalling mechanisms might be involved in the control of stomata in response to decreased soil water availability, hydraulic signals playing the dominant role.

 

Stomata of Vitis (dicots)

Photo credit: Scielo

Comparative leaf micromorphoanatomy of Vitis vinifera ssp. vinifera(Vitaceae) red cultivars

Micromorfoanatomia foliar de cultivares tintas de Vitis vinifera ssp.vinifera (Vitaceae)

by Monteiro A., Teixeira G., Lopes C. M. (2013)

Ana Monteiro, Generosa Teixeira and Carlos M. Lopes

in Ciência Téc. Vitiv. vol.28 no.1 Dois Portos jun. 2013

SUMMARY

Aiming to characterize and discriminate between four red grapevine cultivars – ‘Aragonez’ (AR), ‘Cabernet Sauvignon’ (CS), ‘Syrah’ (SY) and ‘Touriga Nacional’ (TN) – grown under Mediterranean field conditions, we studied their leaf micromorphoanatomic characteristics under light (LM) and scanning electron microscopy (SEM).

The studied characteristics included those of the epidermis, stomata and hair distribution, and the mesophyll structure. The individual primary leaf area revealed significant differences between cultivars, with the highest value presented by AR and the lowest by CS, while SY and TN gave intermediate values. CS presented a significantly higher leaf specific dry weight value than the other three cultivars, which returned similar values.

Under SEM magnification three types of stomata were identified in all the studied genotypes: sunken, at the same level, and raised above the other epidermal cells. Each cultivar displayed different percentages of these types of stomata: the highest raised-above values were observed in AR; TN had the highest same-level values and the lowest sunken ones; CS revealed the highest values for sunken stomata; while SY returned average values for all the types of stomata. Stomatal density was higher in AR and SY and lower in CS and TN.

The hairs on the lower surface presented a similar woolly aspect in all the studied cultivars, but the mesophyll structure was quite different: CS presented the highest and AR the lowest values for total thickness of the lamina, thickness of palisade and spongy parenchyma, and length and thickness of upper and lower epidermal cells; the values for these leaf features in TN and SY fell between those for CS and AR.

The data suggest that differences in leaf micromorphoanatomy can be used to distinguish between grapevine cultivars. Further studies are needed to confirm whether there is any association between some of these leaf traits – e.g. stomata type and mesophyll structure – and the physiological behaviour observed under field conditions.

Read the article: Scielo

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RESUMO

Este estudo teve por objetivo caraterizar e comparar as características micromorfoanatómicas foliares de quatro cultivares tintas de videira – ‘Aragonez’ (AR), ‘Cabernet Sauvignon’ (CS), ‘Syrah’ (SY) e ‘Touriga Nacional’ (TN) – cultivadas em condições de campo com clima mediterrânico, com recurso à microscopia ótica (LM) e eletrónica de varrimento (SEM). Observaram-se os seguintes carateres foliares: epiderme superior e inferior, estomas, indumento e estrutura do mesófilo. A área foliar da folha principal apresentou diferenças significativas entre cultivares, apresentando AR o maior valor e CS o menor e SY e TN valores intermédios. CS apresentou uma área foliar específica significativamente superior ao das outras cultivares. Por recurso à microscopia eletrónica, identificaram-se três tipos de estomas nas quatro cultivares – enterrados, ao mesmo nível e elevados em relação às células epidérmicas. A proporção de cada tipo de estoma variou significativamente entre cultivares: AR apresentou uma maior percentagem de estomas elevados; TN os maiores valores de estomas ao mesmo nível e os menores dos estomas enterrados; CS os maiores valores de estomas enterrados; enquanto SY apresentou percentagens intermédias dos três tipos de estomas. A densidade estomática foi maior em AR e SY e menor em CS e TN. O indumento da página inferior foi semelhante nas quatro cultivares. A estrutura do mesófilo apresentou diferenças significativas entre as quatro cultivares. Os maiores e menores valores da espessura total do limbo, do parênquima clorofilino em paliçada e lacunoso e do comprimento e espessura das células da epiderme superior e inferior foram apresentados pelo CS e AR, respetivamente, enquanto que a TN e a SY apresentaram valores intermédios destes carateres. Os resultados mostram diferenças significativas na micromorfoanatomia foliar dos genótipos estudados sublinhando a necessidade de mais estudos para averiguar possíveis interações entre carateres anatómicos foliares – tipo de estomas e estrutura do mesófilo, por exemplo – e respostas fisiológicas observadas em condições de campo.