Stomata in inter-specific hybrids between P. alba and P. euphratica

Photo credit: Google

Populus alba

Inducing genetic variation in growth related characteristics of poplar germplasm, by producing inter-specific hybrids between P. alba and P. euphratica

by Mirzaie-Nodoushan H., Ghamari-Zare A., Tavousi Rad F., Yousefifard M. (2015)


Mirzaie-Nodoushan H., Forests and Rangelands Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, I.R. Iran.

Ghamari-Zare A., Forests and Rangelands Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, I.R. Iran.

Tavousi Rad F., Payam-Noor University, Isfahan, I.R. Iran.

Yousefifard M., Payam-Noor University, Tehran, I.R. Iran.


in Silvae Genetica 64, 5–6 (2015)

Populus euphratica –


Crosses were made between two Populus species to create two hybrid groups, P. alba (f) * P. euphratica (m) and P. euphratica (f) * P. alba (m) . Aseptic immature hybrid seeds were first grown on MS medium. Hybrid seedlings were then acclimatized and grown in greenhouse conditions and transplanted to an experimental field.

Growth related characteristics were recorded on 307 three years-old seedlings of new inter-specific hybrids of six half-sib families, in order to assess possible potentials of the two hybrid groups.

Double nested analysis of variance revealed significant differences between the hybrid groups and siblings based on majority of the studied characters. The hybrid groups formed two distinct groups for some of the studied characteristics which implied maternal effects of inheritance on the traits.

The first hybrid group had more but shorter and closer branches than the second group. Adaxial stomata number for the two hybrid groups varied between 4.7 to 123. Whereas, there were no such strong differences between vegetative characteristics of the two groups.

The second hybrid group had a very condense layer of white fuzz on its abaxial leaf surface, inherited from its female parents. This may lead to suggest some kinds of photosynthesis and respiration functions such as leaf sub-stomatal chambers’ functions for the mentioned fuzzy trichomes of the second hybrid group and their female parental species, P. alba.

In essence, 307 new divergent poplar hybrid genotypes were produced by which ecological zone of poplar species could be extended in the country as well as high yielding genotypes would be promising.



Stomata, light and CO2


Stomatal responses to light and carbon dioxide in the hart’s-tongue fern, Phyllitis scolopendrium Newm.

by Mansfield T. A., Willmer C. M. (1969)

in New Phytol. 68 : 63-66.



MeJA signaling and signal crosstalk between MeJA and ABA pathways in stomata


Methyl jasmonate signaling and signal crosstalk between methyl jasmonate and abscisic acid in guard cells.

by Munemasa S., Mori I. C., Murata Y. (2011b)

The Graduate School of Natural Science and Technology; Okayama University, Tsushima-Naka, Okayama, Japan.

in Plant Signaling & Behavior. 2011b;6:939–941. -PMID:21681023PMCID:PMC3257766 –

 [PMC free article] [PubMed] –

Proposed MeJA signaling pathway and signal crosstalk between MeJA and ABA in Arabidopsis guard cells. MeJA induces ROS and NO production in guard cells. RCN1-regulating PP2As are involved in this step. The major ROS sourses are NAD(P)H oxidases AtrbohD/F. NOS activity seems to be important for MeJA-induced NO production, but genes encoding NOS have not been indentified in plants. ROS and NO evoke guard cell [Ca2+]cyt elevation by Ca2+ influx from apoplast and from intracellular stores, respectively. ICa channels mediate Ca2+ influx from apoplast. Elevated [Ca2+]cyt is sensed by CDPKs including CPK6 and finally activates S-type anion channels. The abi2-1 mutation disrupts ROS-mediated ICa channel activation. The abi2-1 mutation also disrupts NO-dependent signal pathway, but the details are still unclear. Two myrosinases TGG1 and TGG2 are also involved in the signal crosstalk. –

Plants tightly control stomatal aperture in response to various environmental changes.

A drought-inducible phytohormone, abscisic acid (ABA), triggers stomatal closure and ABA signaling pathway in guard cells has been well studied.

Similar to ABA, methyl jasmonate (MeJA) induces stomatal closure in various plant species but MeJA signaling pathway is still far from clear.

Recently we found that Arabidopsis calcium dependent protein kinase CPK6 functions as a positive regulator in guard cell MeJA signaling and provided new insights into cytosolic Ca2+-dependent MeJA signaling.

Here we discuss the MeJA signaling and also signal crosstalk between MeJA and ABA pathways in guard cells.

Stomatal responses to humidity


Testing a vapour-phase model of stomatal responses to humidity.

by Mott K. A., Peak D. (2013)

Keith cropped
Keith A. Mott, Biology Department , Utah State University, Logan, Utah
David Peak, Physics Department , Utah State University, Logan, Utah

in Plant, Cell & Environment 36, 936944. – DOI: 10.1111/pce.12026 – 

Wiley Online LibraryCAS –


This study tests two predictions from a recently proposed model for stomatal responses to humidity and temperature. The model is based on water potential equilibrium between the guard cells and the air at the bottom of the stomatal pore and contains three independent variables: gs0, Z and Θ.

gs0 is the value of stomatal conductance that would occur at saturating humidity and will vary among leaves and with CO2 and light. The value of Z is determined primarily by the resistance to heat transfer from the epidermis to the evaporating site and the value of Θ is determined primarily by the resistance to water vapour diffusion from the evaporating site to the guard cells.

This leads to the two predictions that were tested. Firstly, the values of Z and Θ should be constant for leaves of a given species grown under given conditions, although gs0should vary among leaves and with light and CO2. And secondly, the ratio of Z to Θ should be higher in leaves having their stomata in crypts because the distance for heat transfer is greater than that for water vapour diffusion.

Data from three species, Nerium oleander, Pastinaca sativum and Xanthium strumarium support these two predictions.

Drought-tolerance and stomatal closure


Plants resistance to drought relies on early stomata closure

Martin-StPaul N., Delzon S., Cochard H. (2017)
Nicolas Martin-StPaul,
Sylvain Delzon,
Hervé Cochard

Paleobotany, climate change and stomata

Photo credit: The Irish Times

Prof Jennifer McElwain (right) and Dr Claire Belcher, with plants in a carbon dioxide atmosphere chamber, as part of the programme for experimental atmosphere and climate, at UCD Thornfield. Photograph: Eric Luke

Our climate is changing at a faster pace than ever before in geological history’

Research Lives: Prof Jennifer McElwain, UCD School of Biology and Environmental Science

by Claire O’Connell

You are a paleobotanist – what does that mean?

“Paleo” means old and “botany” means the scientific study of plants. So I study fossil plants, many of them older than the dinosaurs. These ancient plant remains can tell us a lot about climate change in the past.

Where is the most interesting site that you have collected plant fossils?

Astartekløft, in east Greenland within the Arctic Circle. A team of five of us were helicoptered there in July 2000 for a National Geographic expedition. We spent four wonderful weeks digging up 200-million-year-old fossils, avoiding polar bears and eating Parmesan cheese and salami sausage.

We collected more than 4,500 fossil plants and spent the next decade trying to piece together the ancient landscapes that the fossils revealed, and how plants in the past responded to natural global warming events caused by volcanism.

How do you figure out ancient plant survival tactics?

Using the fossils we worked out how many species were around in Greenland over 200 million years ago, then we reconstructed the climate of the time and tracked the fossil species to examine which went extinct and which survived global warming.

We discovered that generalist plant species survived better than specialists, which were more likely to go extinct as the climate warmed. A good example of a generalist is a species that does not rely on another species to reproduce (that other species may go extinct!) but uses the wind to reproduce.

We also saw that when there is a small amount of carbon dioxide in the atmosphere, leaves have lots of tiny openings or pores called stomata. However, when the amount of carbon dioxide in the atmosphere increases, the plants tend to develop far fewer stomata.

Read the full article: The Irish Times