Page 52 - BCI Bonsai & Stone Appreciation Q1 2025

production is closely related to aerenchyma cell devel-
opment under hypoxic conditions and promotes ET
synthesis in roots. At the same time, ET induces ROS-
mediated cortical cell death, leading to aerenchyma
formation. ET accumulates in roots under waterlogging
because its biosynthesis continues while the rate of
diffusion in water is low. ET stimulates programmed
cell death that occurs during lysogenic aerenchyma
formation. ET response factor (ERF) is an important
transcription factor involved in plant responses to
various biotic and abiotic stresses. ERF family genes
specifically induce genes containing AGCCGCC and
cis DRE/CRT elements, which activate or inhibit the
expression of downstream functional genes and thereby
mediate plant tolerance to various stresses.
This is a brief overview of how our trees respond
to changes in water availability that can result in
stressful conditions. As we look at our bonsai, we have
to remember that they are living organisms with a
myriad of reactions happening in response to every
signal around them. Water is by far one of the most
critical factors for life, and proper watering is crucial
for our bonsai to grow healthier and recover. Needless
to say, a lot is going on inside, even when conditions
are not optimal.
About the Authors:
Dr. Luis Carlos Rodriguez Zapata did his Ph.D at the
Yucatan Research Center. He carried out a postdoctoral
fellowship in the Department of Biochemistry and Cell
Biology, State University of New York at Stony Brook.
New York. He currently is a lab head at the Yucatan
Research Center in the biotechnology department.
Dr. Enrique Castaño did his Ph.D in biochemistry and
biophysics at the University of Rochester. He did post-
doctoral work at Harvard University and the Marie Curie
Research Center in the UK. He currently is a lab head at
the Yucatan Research Center in the Integrative Biology
Department.
Practical Advice:
The information in this article provides bonsai practitio-
ners with a deeper understanding of how water affects plant
physiology, which can improve their watering practices and
overall tree care. Here’s how it can be practically useful:
1. Optimizing Watering Techniques
• Recognizing Water Stress: Understanding the physiological
signs of water stress, such as wilting leaves, helps practitioners
identify early issues before significant damage occurs.
• Preventing Overwatering: Knowing that excessive water
can lead to root rot and oxygen deprivation encourages careful
monitoring of soil drainage and moisture levels.
2. Tailoring Watering to Tree Needs
• Species-Specific Care: Different species have varying
tolerances to water availability. For example, junipers are
more susceptible to improper watering compared to species
like Bald Cypress that can handle waterlogging.
• Adaptation to Environmental Factors: Practitioners can
adjust watering based on temperature, humidity, wind, and
substrate type, minimizing the risk of water-related stress.
3. Improving Substrate and Container Choices
• Understanding the role of field capacity and permanent wilting
points highlights the importance of choosing substrates that
retain sufficient water while allowing drainage.
• Using appropriate containers (e.g., porous versus glazed) can
enhance water retention or drainage as needed.
4. Recognizing and Preventing Water-Related Stress
• Aerenchyma Formation in Waterlogged Species:
Understanding how certain species adapt to waterlogging
helps practitioners identify candidates for unique techniques
like bog-style bonsai.
• Root Growth and Stress Adaptation: Knowing that roots
grow in response to water deficits informs pruning techniques
and pot size selection.
5. Disease Prevention
• Awareness of how waterlogging facilitates fungal and bacterial
infections can prompt actions like avoiding standing water,
improving aeration, or adjusting watering schedules.
6. Using Hormonal Responses for Training
• Understanding how hormones like abscisic acid (ABA)
regulate stress responses helps practitioners predict how trees
might adapt to pruning or defoliation, especially under water-
limited conditions.
7. Planning Seasonal Care
• Trees may require different watering strategies during
dormancy, active growth, or periods of environmental stress.
Knowledge of these processes can guide seasonal adjustments
to care.
Practical Example:
A bonsai practitioner observing wilting leaves in a juniper
might recall that it could indicate insufficient water uptake or
overwatering causing root damage. By checking soil moisture
levels and adjusting watering practices accordingly, they can
prevent further decline. Additionally, selecting a well-draining
substrate helps avoid repeated waterlogging issues.
By applying this scientific knowledge, bonsai practitioners
can make more informed decisions, resulting in healthier trees
and greater success in their art.
Questions about this article? Email the editor and we’ll
forward your questions to the authors.
50 | BCI | January/February/March 2025