Fluctuations in cell cycle, morphology and metabolism of Anemia phyllitidis gametophytes are the most important hallmarks of GA3-induced antheridiogenesis

The research object concerns partially explained mechanisms of plant hormone participation in male sex determination in plants, among them in A. phyllitidis gametophytes during GA₃-induced antheridiogenesis. To provide an explanation of the mechanisms of fluorescence and white-light microscopy, cytophotometric, autoradiographic and spectrophotometic methods were used to study cell cycle, the number of nucleoli, the amount of DiOC₆-stained IMN/ER, in which endoplasmic reticulum (ER) constitutes the main part, and its distribution as well as the amounts of proteins and chlorophylls and activities of acidic (Ac) and basic (Ba) phosphatases (Phases). It was revealed that antheridiogenesis was accompanied by cell cycle arrest at S-phase, changes of the number of nucleoli with simultaneous changes of the amount of IMN/ER and its distribution as well as fluctuations of protein amounts and of activities of acidic (Ac) and basic (Ba) phosphatases (Phases). The results indicated that initiation of antheridiogenesis in A. phyllitidis gametophytes by GA₃ was related to the elevation of GAs/ANs in the culture media, during its induction phase, and the elevation of IMN/ER and GAs/ANs amounts, during expression phase of this process.

A gateway with a guard: how the endodermis regulates growth through hormone signaling

The endodermis is a defining feature of plant roots and is most widely studied as a differentially permeable barrier limiting solute uptake from the soil into the vascular stream. Recent work has revealed that this inner cell layer is also an important signaling center for hormone-mediated control of growth. Auxin, gibberellic acid, abscisic acid and strigalactones all appear to depend on the endodermis to regulate root biology and point to this cell type as having important inter-cell layer regulatory activity, as well. In this review I discuss recent work detailing the importance of the endodermis in growth control and how this function is affected during responses to the environment.