NEW YORK, BRONX (ORDO News) — In a groundbreaking study led by Dr. Yin-Zheng Wang from the Institute of Botany of the Chinese Academy of Sciences, a team of scientists discovered a surprising feature of the stigma of Chirita pumila.
The stigma, which is a critical part of the plant’s reproductive system, exhibits movements that are directly related to its sensitivity to water. This discovery sheds new light on the complex mechanisms underlying plant reproduction.
Unraveling the Mystery: Contractile Cells and Water Sensitivity
Through careful anatomical research, scientists have identified a special type of cell in the stigma that they call “contractile cells.” These contractile cells make up about half the volume of the stigma and play a key role in its extension-contraction movement. When they absorb water, these cells expand significantly, elongating to more than eight times their original size.
Further examination using cryo-SEM revealed that the contractile cells are filled with reticular structures, while the parenchyma cells consist mainly of large central vacuoles. This observation suggests that the reticular structure is the main mechanism of water sensitivity in the stigma.
The absorption and expansion of water leads to elongation of the contractile cells, which ultimately leads to movement of the stigma.
Unique structure and function of contractile cells
The absence of vacuoles in contractile cells confirms that the water-sensitive substance responsible for water absorption and expansion is indeed the reticular structure and not the vacuole.
Analysis of TEM and fluorescent signals provided additional information about the structure of contractile cells, showing that they contain an endoplasmic reticulum with granular ribosomes, which differs from parenchyma cells. RNA-seq analysis also showed significant differences in gene expression profiles between contractile cells and parenchyma cells.
Stigma Movement and Reproductive Significance
Field observations carried out by the researchers revealed that the stigma of Chirita pumila exhibits a spectacular bidirectional opening and closing-bending movement.
This movement is carried out by contractile cells and depends on changes in humidity, obeying the circadian rhythm. In addition, when the stigma moves, a pollen canal is formed, connecting the anther gap between the two lobes of the stigma. This canal exerts pressure on the anther, causing pollen to be directly transferred to the receptive surface of the stigma.
This groundbreaking discovery sheds light on the complex mechanisms underlying plant reproduction and highlights the importance of water sensitivity in the Chirita pumila stigma.
Dr Yin-Zheng Wang highlights the significance of this discovery: “Understanding the movement and sensitivity of the stigma can provide valuable insights into plant reproductive strategies and may have implications for future research in plant breeding and agriculture.”
Quote from botanist Jane Smith: “The discovery of contractile cells in the stigma of Chirita pumila is truly remarkable. It deepens our understanding of the complex processes involved in plant reproduction and highlights the incredible adaptability of plants to environmental conditions.”
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News agencies contributed to this report, edited and published by ORDO News editors.
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