Adaptations of succulent plants for survival in desert ecosystems

Abstract

Cilj ovog seminara bio je nabrojati prilagodbe sukulentnih biljaka koje su im nužne za preživljavanje u pustinjskim ekosustavima. Sukulenti su biljke koje imaju posebne morfološke i ekofiziološke prilagodbe za pojačano primanje i pohranu vode. Razlog zašto bez takvih prilagodbi ne bi mogle preživjeti je što žive u pustinjama i polupustinjama, aridnim područjima u kojima je voda glavni ograničavajući čimbenik. Kiša pada rijetko i uglavnom nepredvidljivo, tlo ne može primiti puno vode pa ju biljke moraju u najkraćem mogućem vremenu skupiti u što većim količinama. Neke biljke sušno razdoblje preživljavaju u obliku sjemenki, neke ispod zemlje, a neke opstaju u punoj veličini i prkose suši. Sukulenti koriste CAM fotosintezu, da bi puči mogli držati otvorene samo po noći i tako smanjiti transpiraciju. Moraju imati posebna tkiva za spremanje vode, a stanice hidrenhima moraju imati elastične stijenke kako bi mogle podnositi velike razlike u volumenu vode bez velike promjene u turgoru. Razgranat i plitak korijenski sustav pomaže u primanju vode za vrijeme kiše. Kloroplasti se od prejake radijacije, koja bi mogla izazvati fotoinhibiciju, štite skupljanjem u nakupine. Sve ove, i mnoge druge prilagodbe, čine sukulente izuzetno zanimljivom skupinom biljaka.The goal of this seminar was to list the adaptations of succulent plants that are necessary for their survival in desert ecosystems. Succulents are plants that have special morphological and ecophysiological adaptations for increased water uptake and storage. The reason why they could not survive without such adaptations is that they live in deserts and semi-deserts, arid environments in which water is the main limiting factor. Precipitation is rare and occurs randomly, the soil cannot uptake a lot of water, so the plants have to collect as much as possible of it in the shortest possible amount of time. Some plants survive the dry period in the form of seeds, some survive mostly under the ground, while others persist above ground in their full form and defy the drought. Succulents use CAM photosynthesis in order to be able to minimize transpiration by only keeping the stomata open at night. They have special water-storage tissues, and the hydrenchyma cells need to have high elasticity cell walls in order to withstand big differences in water volume, without a significant turgor change. The ramified and shallow root system helps uptake water during rain. Chloroplasts protect themselves from too high radiation, that could cause photoinhibition, by clustering together. All of the above, as well as many other adaptations, make succulents an extremely interesting group of plants