How do cactus hold water

In addition, the Laplace pressure gradient is caused by the trichome's cone shape and the surface energy gradient. This result is similar to the function of cactus spines for the directional movement of water droplets toward the epidermis of cactus stem Ju et al. In general, hydrophilic surfaces have high affinity to water Adamson and Gast, Thus, the hydrophilic surface is advantageous in obtaining moisture from the atmosphere.

However, the collected water droplets have to be rapidly absorbed into the stem, because the surrounding temperature is high and humidity is low in arid areas and deserts, which favors rapid evaporation. To achieve fast water absorption, water evaporation procedure is not always required. When a water droplet forms a certain shape which can induce Wenzel state on the trichome surface in any way, it can be abruptly absorbed into the stem.

Water droplets can penetrate spontaneously from the hydrophobic layer toward the hydrophilic layer. Conversely, the opposite directional transport is strictly restricted because the absorbed water is blocked and spread into the hydrophilic region Tian et al. In a previous study, the reason for this phenomenon was theoretically analyzed. The anisotropic critical breakthrough pressure Pc is larger in the downward direction from hydrophobic to hydrophilic compared with the upward direction from hydrophilic to hydrophobic because of the coupling effect Tian et al.

If the wettability of the trichome cluster is hydrophilic, then the trichome cluster is better for collecting water from air. The proposed nature-inspired in vitro system is easy to fabricate and can be utilized in the design of efficient water absorption and storage system. In addition, the present results are useful not only for understanding the underlying water absorption and storage strategies of cacti but also for providing the experimental data required to develop a new biomimetic water collection device.

KK and SL proposed the study. KK and HK analyzed experimental data and processed images. All authors discussed the results. KK wrote the paper. All authors participated in completing the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

National Center for Biotechnology Information , U. Journal List Front Plant Sci v. Front Plant Sci. Published online Oct Author information Article notes Copyright and License information Disclaimer. Received Jul 4; Accepted Sep The use, distribution or reproduction in other forums is permitted, provided the original author s or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice.

No use, distribution or reproduction is permitted which does not comply with these terms. This article has been cited by other articles in PMC. Associated Data Supplementary Materials Video1. AVI K. AVI 10M. AVI 5. AVI 1. Abstract Being an essential component in various metabolic activities, water is important for the survival of plants and animals.

Keywords: cactus, water absorption, water storage, water pathway, survival strategy. Introduction Water is one of the most important elements not only for human beings but also for plants, because it is highly essential for various metabolic activities Hanson and Hitz, ; Kim et al. Open in a separate window. Figure 1. Materials and methods Wettability test The wettability of a cactus stem was examined using Nile red, a fluorescent hydrophobic probe.

Fabrication of a cactus trichome-inspired system A cactus trichome-inspired system was fabricated in this study. Results Structural characteristics of the trichome cluster of cactus The structural characteristics of the cactus Opuntia microdasys OM , which is a fog collector representative, were analyzed using various advanced imaging techniques.

Figure 2. Figure 3. In vitro water absorption experiment using a cactus-inspired model To further understand water management strategies of cacti, a cactus-inspired double-layered water absorption in vitro model was designed. Figure 4. Table 1 Physical properties of the three meshes tested in this study. Discussion The trichome cluster of a cactus stem has unique structural features to survive in harsh arid areas. Author contributions KK and SL proposed the study.

Conflict of interest statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Footnotes Funding. Click here for additional data file. References Adamson A. Physical Chemistry of Surfaces, 6th Edn. Facile and large-scale fabrication of a cactus-inspired continuous fog collector. Application of Nile red, a fluorescent hydrophobic probe, for the detection of neutral lipid deposits in tissue sections: comparison with oil red O.

Nile red: a selective fluorescent stain for intracellular lipid droplets. Cell Biol. Metabolic responses of mesophytes to plant water deficits. Plant Physiol. Branched ZnO wire structures for water collection inspired by cacti. ACS Appl. Interfaces 6 , — A multi-structural and multi-functional integrated fog collection system in cactus. Bioinspired conical copper wire with gradient wettability for continuous and efficient fog collection.

Cactus stem inspired cone-arrayed surfaces for efficient fog collection. Novel water filtration of saline water in the outermost layer of mangrove roots. Superhydrophobic states.

Hydrophobic—hydrophilic dichotomy of the butterfly proboscis. Some extreme drought-prone cactuses have the ability of water storage even in their root system. They can absorb and retain water for a long time using these abilities. When it rains, it pours. So incidentally they have developed a stunning water management system that firstly helps in the absorption and collection of water through.

Cactuses store this water in the mucilage cells located in the stems and sometimes even in the roots Source. Plants in the water sufficient areas generally use only a small portion of the water absorbed for growth, the rest of it gets lost by the process of leaf transpiration. However, cactuses do not have that luxury and manage every drop of water available carefully to survive. The basic adaptations that have helped cactuses to store water for a long time, put up with drought in the desert areas, and to prevent water loss are as follows:.

The stem has in due course of time evolved to be thick and fleshy in the inside that ensures proper spacious storage space for water and is covered with thorns and wax from outside that protects and prevents water loss respectively. Cacti Adaptation. Cacti have many adaptations that allow them to live in dry areas; these adaptations let the plant collect water efficiently, store it for long periods of time, and conserve it minimizing water loss from evaporation.

Cacti have a thick, hard-walled, succulent stem — when it rains, water is stored in the stem. The stems are photosynthetic , green, and fleshy. The inside of the stem is either spongy or hollow depending on the cactus.