Study on the Relationship Between the Ploidy Level of Microspore-Derived Plants and the Number of Chloroplast in Stomatal Guard Cells in Brassica oleracea

The relationship between the ploidy level of microspore-derived plants and chloroplast number in stomatal guard cells was studied in cabbage, broccoli, and Chinese kale. In the experiment, distribution statistics analysis and t-test were used to perform statistical analysis on chloroplast number of different ploidy level in those stomatal guard cells mentioned above, and morphology identifying and chromosome counting were used to test accuracy of counting chloroplast number in stomatal guard cells. The chloroplast average number in stomatal guard cells was very similar among the different leaf positions on the same plant and among significantly among the different ploidy the different locations in the same stoma in the same variety. All the leaf, while the chloroplast number varied distributions of the chloroplast number in different ploidy stoma were normal distribution fitted. A correlation has been established between ploidy and chloroplast number in the stomatal guard cells. In every single stoma of microspore-derived plants, the chloroplast number for a haploid should not be more than 10, diploids 11 to 15, and polyploids more than 15. The accuracy of this method for identification of different ploidy plants was 93.93%. Furthermore, the accuracy of this method was reliable and did not vary with the plants growth conditions. Therefore, the chromosome ploidy of plants derived from microspore culture in cabbage, broccoli, and Chinese kale can be identified by simply counting the chloroplast number in stomatal guard cells.

Involvement of Calcium dependent Protein Kinases in ABA regulation of Stomatal Movement

Patch clamp techniques were employed to investigate if calcium dependent protein kinases (CDPKs) be involved in the signal transduction pathways of stomatal movement regulation by the phytohormone abscisic acid (ABA) in Vicia faba. Stomatal opening was completely inhibited by external application of 1 μmol/L ABA, and such ABA inhibition was significantly reversed by the addition of CDPK inhibitor trifluoperazine (TFP). The inward whole cell K + currents were inhibited by 60% in the presence of 1 μmol/L intracellular ABA, and this inhibition was completely abolished by the addition of CDPK competitive substrate histone Ⅲ S. The results suggest that CDPKs may be involved in the signal transduction cascades of ABA regulated stomatal movements.

Interplay between hydrogen sulfide and other signaling molecules in the regulation of guard cell signaling and abiotic/biotic stress response

Stomatal aperture controls the balance between transpirational water loss and photosynthetic carbon dioxide(CO2)uptake.Stomata are surrounded by pairs of guard cells that sense and transduce environmental or stress signals to induce diverse endogenous responses for adaptation to environmental changes.In a recent decade,hydrogen sulfide(H2S)has been recognized as a signaling molecule that regulates stomatal movement.In this review,we summarize recent progress in research on the regulatory role of H2S in stomatal movement,including the dynamic regulation of phytohormones,ion homeostasis,and cell structural components.We focus especially on the cross talk among H2S,nitric oxide(NO),and hydrogen peroxide(H2O2)in guard cells,as well as on H2S-mediated post-translational protein modification(cysteine thiol persulfidation).Finally,we summarize the mechanisms by which H2S interacts with other signaling molecules in plants under abiotic or biotic stress.Based on evidence and clues from existing research,we propose some issues that need to be addressed in the future.