Suberized transport barriers in plant roots: the effect of silicon

Abstract

Plant roots are the major organs that take up water and dissolved nutrients. It has been widely shown that apoplastic barriers such as Casparian bands and suberin lamellae in the endo- and exodermis of roots have an important effect on regulating radial water and nutrient transport. Furthermore, it has been described that silicon can promote plant growth and survival under different conditions. However, the potential effects of silicon on the formation and structure of apoplastic barriers are controversial. A delayed as well as an enhanced suberization of root apoplastic barriers with silicon has been described in the literature. Here we review the effects of silicon on the formation of suberized apoplastic barriers in roots, and present results of the effect of silicon treatment on the formation of endodermal suberized barriers on barley seminal roots under control conditions and when exposed to osmotic stress. Chemical analysis confirmed that osmotic stress enhanced barley root suberization. While a supplementation with silicon in both, control conditions and osmotic stress, did not enhanced barley root suberization. These results suggest that enhanced stress tolerance of plants after silicon treatment is due to other responses.

Molecular Cloning and Functional Analysis of GmLACS2-3 Reveals Its Involvement in Cutin and Suberin Biosynthesis along with Abiotic Stress Tolerance

“…Cutin is deposited on the surface of aerial parts together with wax, providing a protective layer against water loss [1,2,7], while suberin is scattered in root endodermis and also prevents the leakage of water and solutes from roots [27,28]. Therefore, both polymers are important for plant water retention capacity.…”

Hydroponic cultivation conditions allowing the reproducible investigation of poplar root suberization and water transport

“…4 c). This classification into functional developmental zones enables high comparability to earlier studies on barley [ 5 , 40 , 52 ], but also other monocotyledonous [ 26 ] as well as dicotyledonous [ 27 , 33 ] crop species.…”

“…Researchers from various laboratories are actively investigating stress physiological responses of plants which are often associated with the more and more prominent effects of global warming or human agriculture and agroforestry. These effects include prolonged periods of drought or flooding, an increase of soil salinity, or exposure to heavy metals [ 1 – 5 ]. Scientific joint ventures are frequently undertaken to not only unravel and understand the coping mechanisms of plants, but also to propose potentially helpful breeding technologies, beneficial genetic modifications, or more efficient cultivation approaches for the future.…”

“…The frequent study of root apoplastic barriers (Casparian bands and suberin lamellae) as plant means to adapt to changing environmental conditions in many crop species [ 26 – 33 ] has already led to the refinement of a set of highly elaborate methodologies which are readily available to be adjusted to the increasingly important poplar root research. However, it has been discussed before that either method on its own is not sufficient to reliably elucidate the complex structures, properties, and interactions of suberized transport barriers in roots [ 5 , 34 ]. It is especially the combination of protocols for consistent plant cultivation, histochemistry, biochemical investigation, transcriptomics, and final functional studies investigating transport physiology that will enable the best comparability to previously published research [ 21 , 22 , 35 – 47 ].…”

Hydrogen peroxide modulates lignin and silica deposits in sorghum roots

“…Many of these works point to Si-generated effects on plants’ oxidative state including gene regulation, protein abundance and ROS levels (Cooke and Leishman, 2016), first suggested by (Chérif et al, 1994). A specific example in root endodermis shows that the supplementation of silicic acid to the growing medium enhances lignification (Fleck et al, 2011; Lukačová et al, 2013) but not suberization (Kreszies et al, 2020) through modulation of ROS and ROS-dependent enzymes (Fleck et al, 2011). In this work, we show a reciprocal effect: The apoplastic oxidative levels affect the extent of endodermal silicification in roots of sorghum seedlings through mediation of lignin formation.…”