Initial Phases of Antarctic Ramalina terebrata Hook f. & Taylor Thalli Rehydration Observed by Proton Relaxometry

Abstract

Hydration kinetics, sorption isotherm, and proton free induction decays are measured for Ramalina terebrata thalli rehydrated from gaseous phase. Very tightly, tightly, and loosely bound water fractions are distinguished. Sorption isotherm is sigmoidal in form with the mass of water saturating primary water binding sites equal to ∆m/m 0 = 0.046. Proton free induction decays show the presence of immobilized water fraction (T * 2L 1 ≈ 100 µs) and mobile water pool (T * 2L 2 ≈ 330 µs). Sorption isotherm fitted to the NMR data shows the absence of water fraction "sealed" in pores of dry thallus.

A method of water-soluble solid fraction saturation concentration evaluation in dry thalli of Antarctic lichenized fungi, in vivo

“…Its relative mass is close to that obtained for other species of Antarctic lichens, e.g . for fruticose Usnea antarctica Du Rietz =0.040±0.011, [6] , and for foliose Umbilicaria aprina Nyl. =0.054±0.011 [7] .…”

“…The sorption isotherm for other Antarctic lichens is also better fitted using Dent model, e.g. for Leptogium puberulum b =0.955 [8] , for Umbilicaria aprina b =0.941 [7] , and for Usnea antarctica b =0.913 [6] .…”

“…in cellular organelles such as freeze-dried photosynthetic membranes [1] , [2] ; in plant tissues like horse chestnut bast [3] ; at the initial phases of seed imbibition [4] , as well as in whole living organisms, e.g . in thalli of several species of lichenized fungi [5] , [6] , [7] , [8] , [9] .…”

Non-cooperative immobilization of residual water bound in lyophilized photosynthetic lamellae

“…To analyze the applicability of the Gaussian approximation for a description of the solid FID component, we calculated the relationship between M 2 , M 4 and M 6 for rehydrated wheat photosynthetic lamellae as a function of the hydration level. For the whole range of hydration levels investigated, we got the averaged values: for other dry biological microheterogeneous systems, such as the solid matrices of bark or bast [24], lichen thalli [25][26][27][28], arthropod cuticle [29], human terminal hair [30], and dentine and dental enamel [31]. Pintar [32] was the first to suggest that the striking similarity in values of * S T for a variety of different biological systems is a result of a similar distribution of local magnetic fields for a limited Brought to you by | University of North Carolina at Chapel Hill Authenticated Download Date | 10/10/15 3:59 AM number of chemical groups forming the biological system at a submolecular scale.…”

“…In human dentine, the * 2 T  60 s fraction was interpreted as a "rigid water" signal component [34]. In other dry microheterogeneous systems, such as the inner surfaces of bark and bast [24], lichen thalli [25][26][27][28], atrhropod cuticle [29] and human terminal hair [30], such a signal was assigned to the water fraction tightly bound to the lyophilizate. The increase in the tightly bound water fraction L 1 versus increased hydration level is not very substantial but it is noticeable.…”