While lateral roots comprise the bulk of root length, axial roots function as a scaffold determining the distribution of these laterals.
Continue reading Soil compaction and nitrate capture
Mountain forests are important ecosystems subject to extreme climate conditions. Soil buffers root systems against variations in the weather, but we know little of how climate affects tree root growth and mortality. Wang et al. installed rhizotrons in mountain forests at different altitudes and measured root growth and mortality every month for 4 years. They find that root elongation is mostly driven by soil temperature between zero and 8°C and was lower in cold soils. At 2000 m, short-lived, fine roots were more numerous, compensating for the short growing season. Soil water had little effect on root growth or mortality.
Continue reading Tree root dynamics in mountain forests
Boron (B) is essential for plant growth, but hazardous when present in excess. Hydrogen gas (H2) possesses antioxidant properties. Wang et al. investigate B-induced biological responses during rice (Oryza sativa) seed germination to study the beneficial role of H2. In addition to the capacity of H2 to re-establish equilibrium where there is a reactive oxygen species (ROS) imbalance, H2 tolerance to B toxicity is shown to result in improved root elongation and water status, up-regulation of genes encoding specific aquaporins (AQPs) and reduced B accumulation. The increased transcription of representative AQPs genes and BOR2 along with the decreased BOR1 mRNA...
Continue reading Boron toxicity tolerance mediated by H2 during rice seed germination
Studying the influence of soil strength on root growth dynamics, Popova et al. document the mechanical and tropic responses of primary roots of maize (Zea mays) seedlings further to penetration of a bilayered soil consisting of loose loamy sand on top and a coarser, denser layer beneath. Upon reaching the compacted soil in the lower layer, the elongation rate of the primary roots nearly halved and the tortuosity and deflection of the root path significantly changed in response to contact with the changing soil texture. The resulting ‘waviness’ of the root serves as a key indicator of the maize roots’...
Continue reading Maize root growth responses to penetration of a bilayered soil
One of the best-known effects of the plant hormone auxin on plant development is the inhibition of root elongation, yet the underlying mechanism remains poorly understood. Using tomato (Solanum lycopersicum) as a model, Ivanchenko et al. demonstrate that auxin acts by increasing the level of hydrogen peroxide (H2O2) in the root tip. Increasing the auxin level triggers accumulation of H2O2, leading to inhibition of root cell elongation and root growth. The diageotropica (dgt) mutation in tomato, which confers auxin resistance, affects this pathway by reducing the auxin responsiveness of tissues and by disrupting the H2O2 homeostasis in the root tip.
Continue reading Auxin and H2O2 interaction in control of root growth
Correlative evidence suggests a relationship between the lunisolar tidal acceleration and the elongation rate of Arabidopsis thaliana roots grown under conditions of constant low light. Barlow et al. use high temporal- and spatial-resolution video imaging to study root elongation in conjunction with geophysical variables for seedlings grown in a constant environment. They find that elongation responds not only to variation of the lunisolar force but also seems to adjust to variations in the geomagnetic field, as evaluated from the disturbance storm time and ap indices. They conclude that both lunisolar tidal acceleration and the geomagnetic field should be considered as modulators...
Continue reading Root elongation growth and lunisolar tidal acceleration
Novel border-like cells in woody plant roots Root border cells play a critical role in root growth and microbial association, although their detachment patterns are divergent among plant species. Endo et al. describe a detailed pattern of synthesis, separation and survival of distinct border-like cells that form a sheath surrounding the root apex of a tree, Acacia mangium. The cells bilaterally peel from the entire root apex, mainly in a region 1–3 mm behind the tip and may play a role in the protection of root elongation from adverse growth conditions.
Continue reading Novel border-like cells in woody plant rootsBotany One is a blog run by the Annals of Botany Company, a non-profit educational charity.
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