ERECTA is an ancient family of leucine-rich repeat receptor-like kinases (RLKs) that coordinate growth and development of plant. TaERECTA, one copy of the ERECTA homologs in wheat, was isolated from bread wheat Chinese Spring. The Ser/Thr kinase of TaERECTA was expressed in E. coli after IPTG induction and confirmed by immunoblot. TaERECTA showed higher expression in younger organs with rapid development, as well as great expression in younger spikes at booting stage. Under exogenous application of gibberellin (GA3) and abscisic acid (ABA), and Mg2+ stress, the expression of TaERECTA was largely suppressed, whereas under exogenous application of indole acetic acid (IAA) and brassinolide (BR), and dehydration stress, its expression was initially suppressed and then up-regulated. Natural variation was apparent in the relative expression of TaERECTA among 9 different bread wheat lines, and its expression level was negatively correlated with the stomatal density. These results suggested that TaERECTA could be exploitable for manipulating agronomical traits important through regulating stomata density, with potential implication for bread wheat improvement.
Authors:J.C. Zheng, T. Liu, J.Q. Li, X. Wang, W.Y. Li, F. Xu, and Q.W. Zhan
Barley stripe mosaic virus (BSMV)-based virus induced gene silencing (VIGS) is an effective strategy for rapid determination of functional genes in wheat plants. ERECTA genes are reported to regulate stomatal pattern of plants, and manipulation of TaERECTA (a homologue of ERECTA in bread wheat) is a potential route for investigating stomatal development. Here, the leucine-rich repeat domains (LRRs) and transmembrane domains of TaERECTA were selected to gain BSMV:ER-LR and BSMV:ER-TM constructs, respectively, targeting TaERECTA for silencing in wheat cultivars ‘Bobwhite’ and ‘Cadenza’, to identify the function of TaERECTA on stomatal patterns. The results showed that reduced expression of TaERECTA caused an increased stomatal and epidermal cell density by average 13.5% and 3.3%, respectively, due to the significantly reduced size of leaf epidermal and stomatal cells, and this led to an increase in stomatal conductance. These suggest that modulation of TaERECTA offers further opportunities in stomatal engineering for the adaptation of photosynthesis in wheat.
Authors:D. Palhares, C. Silveira, L. Zaidan, and L. Pereira
is a dioicous species occurring very commonly in the Brazilian cerrado vegetation. Leaves from male and female plants were compared in size and anatomical structure. No differences in size were found. Female plants presented higher stomatal density than the male ones. All other qualitative and quantitative parameters did not show differences related to sex. The leaf blade is amphistomatous. Only spongy mesophyll is present. In the midrib, there are three vascular bundles that fuse into one bundle in about the second third of the foliar length. Idioblasts containing calcium oxalate occur randomly in the petiole and leaf blade. No starch or tannins were evidenced. Nervation is acrodromous.
presents structures similar to other Smilacaceae, however, in the whole, it presents distinctive characteristics from other species of the genus.
Authors:Maria Drapikowska, Karolina Susek, R. Hasterok, P. Szkudlarz, Z. Celka, and B. Jackowiak
Diploid Anthoxanthum odoratum and tetraploid A. aristatum were compared with respect to stomatal guard cell lengths, and stomatal density at adaxial and abaxial surfaces of the lamina. Further, the genome size of both species was determined by flow cytometry, and the number as well as the chromosomal distribution of 5S and 45S rDNAs were examined using FISH with ribosomal DNA (rDNA) probes. The average length of stomatal guard cells in A. odoratum was shown to be greater than that for A. aristatum, but the ranges overlapped. Moreover, reduction in stomatal frequency was found at higher ploidy levels.The genome size was 6.863 pg/2C DNA for A. aristatum and 13.252 pg/2C DNA for A. odoratum. A. aristatum has four sites of 5S rDNA in its root-tip meristematic cells, whereas A. odoratum has six. Both species have six sites of 45S rDNA. Chromosomal localization of the rDNA varied, which suggests that chromosome rearrangements took place during Anthoxanthum genome evolution.
Micromorphological studies revealed the developmental changes in micropropagated plants of Morinda citrifolia L. from in vitro conditions to field environment. The lower relative humidity, higher light intensity and septic stressful conditions in the field environment could make gradual changes in the micropropagated plants so as to adapt the external environment. Arrested stomatal development, single guard cells and indistinct subsidiaries were observed in vitro with highest stomatal density (52.0±0.11) obtained in the ambient in vitro environment. The development of tissues, epidermal ornamentation, efficient stomatal functionality and vein-islets numbers (12.0±0.0) during in vivo transfer may help in acclimation of micropropagated plants under field conditions. Raphides were observed in the in vitro propagated as well as in vivo transferred plantlets. The gradual acclimatisation and ex vitro rooting technique increased the survival rate of plantlets in the field. The micromorphological changes resulting from in vitro to field environments are important to understand the development of tissues and adaptation of micropropagated plants, which could help in improvement in survivability during field trials.
Authors:Irma Tari, D. Camen, Giancarla Coradini, Jolán Csiszár, Erika Fediuc, Katalin Gémes, A. Lazar, E. Madosa, Sorina Mihacea, P. Poor, Simona Postelnicu, Mihaela Staicu, Ágnes Szepesi, G. Nedelea, and L. Erdei
Tari, I. (2003/2004) Abaxial and adaxial stomataldensity, stomatal conductances and water status of bean primary leaves as affected by paclobutrazol.
Biol. Plant. 43