ABSTRACT Plants have evolved complex cell‐type‐specific processes to adapt to a dynamic environment, exhibiting distinct signals in response to emerging drought stress. We propose an advanced qualitative and quantitative analysis approach, demonstrating tissue specificity in drought adaptation, which in turn may provide novel biological insights. This study represents the first comparative immunolocalization of cell components in wheat roots and leaves subjected to graded drought stress. Leaf and root samples of wheat were collected at 0, 5, and 20 days under control and drought conditions, and analysed by confocal microscopy. We performed immunofluorescence labeling of specific cellular components in situ, and the acquired data were analysed in terms of changes in quantitative and spatial fluorescence intensity. The qualitative analysis revealed differences in terms of individual components and individual days of the experiment. The quantitative analysis of leaf anatomy showed that the most pronounced changes were observed in the level of proteoglycans (JIM13, JIM15) and polysaccharides (LM5, LM16, LM20). The leaves of plants growing in drought were characterised by severely deformed tissue regions, in which increased secretion of extensins, AGPs, galactans, hemicelluloses, and RG‐I was noted. In turn, the qualitative analyses of the microscopy images of roots, along with fluorescence intensity analyses, revealed a significantly higher content of AGP and arabinoxylan in the exodermis in plants grown under drought stress. The amount of LM2‐recognised AGPs in the root exodermis increased fourfold after 20 days of drought compared with well‐watered controls. Our research has revealed that the changes at the tissue level are spatially localised and highly specific, highlighting the dynamic nature of cell adaptation in response to water stress. The obtained results also emphasise the importance of in planta analyses, which indicate that findings from only single ex planta studies may distort the entire image of changes occurring in the plant as a result of stress.
Leszczuk et al. (Thu,) studied this question.