SEM Observations on the Root Hairs of Trifoliate Orange Grafted with Satsuma Mandarin under Low Soil Moisture and High Summer Temperature Condition

Abstract

Abstract:The root hairs of trifoliate orange grafted with satsuma mandarin (Citrus unshiu Marc. cv. Okitsu Wase) at low soil moisture (-0.046 to -0.059 MPa) and high summer temperature (40-45EC) condition was studied under scanning electron microscope. The hair zone in actively growing roots positioned far apart from the root terminal and the hairs were mostly smaller with domft-shaped tips. Along with the severity of modification in roots under the present treatment hair zone positioned gradually nearer the root tip and the hairs gradually degraded. As a result the moderately modified roots possessed a few intact hairs but the extremely modified ones had only a few degenerated hairs or they were completely devoid of that. In that case, only the traces of abolished hairs were left with the root epidermis. At the initial stage of modification in roots, hairs elongated and this elongation was also found in the moderately modified roots but they had slightly irregular shapes. As the modification of root hairs progressed, their tips variously malformed having bending or swollen structure or they were severely injured. The malformed or injured root hairs subsequently destroyed completely.

Response of root and root hair phenotypes of cotton seedlings under high temperature revealed with RhizoPot

“…For example, temperature-sensitive Arabidopsis thaliana seedlings were unaffected at normal temperature (20°C) but failed to form root hairs at elevated temperature (30°C), which manifests as a reduction in the root hair length and density ( Kim et al., 2021 ). The root hair number of trifoliate orange decreased at 40°C–45°C ( Mohammad and Shiraishi, 2000 ). N stress significantly shortened the root hair lifespan of cotton but greatly increased its root hair density and length ( Zhu et al., 2022 ).…”