The problem of soil salinity in frut plants from the pumpkin family (Cucurbitaceae)

Bučnice so zelo razširjene in priljubljene plodovke, ki potrebujejo veliko vode. Gojenje v aridnih in semiaridnih območjih zahteva namakanje. Zaradi malo padavin in močne evapotranspiracije lahko koncentracije soli v tleh močno narastejo. Pomanjkanja pitne vode le še stopnjuje problem slanih tal, saj so pridelovalci prisiljeni namakat z vodo, katera ima previsoko koncentracijo NaCl in drugih soli. Zaradi zahtev trga po velikih in kvalitetnih pridelkih je vsako obdelovalno površino treba izkoristit, zato bučevke velikokrat pridelujejo na tleh s povečano koncentracijo soli. Splošno so bučnice tolerantne na slanostni stres, se pa njihova tolerantnost razlikuje. Pri kumarah na primer pride do 50 % izgube pridelka pri slanosti tal izraženi kot elektrokonduktivnost (EC) 6,3 dS/m, bučke imajo takšno izgubo pri 7,9 dS/mlubenice izgubijo polovico pridelka že pri 4,5 dS/m. Posledice gojenja rastlin na slanih tleh so: oviran sprejem vode pri semenih, ko zaradi višjega osmotskega potenciala rastni substrati povzročajo toksičnost, ki spreminja aktivnosti encimov presnove nukleinske kisline, spremeni presnovo beljakovin, moti hormonsko ravnovesje in zmanjšuje izkoriščenost zalog semena. Povečana absorpcija soli povzroči toksične učinke Na+, Cl- ali sulfata (SO42-), ki zmanjšajo sprejem esencialnih mineralov kot so dušik (N), fosfor (P) ter kalij (K) in kalcij (Ca2+), posledica je tudi povišana koncentracija Na+ in Cl- v listih rastlinzmanjšanje fotosintetskih pigmentov, saj se fotosinteza zmanjša, ko se v kloroplastih in klorofilu kopičijo visoke koncentracije Na+ in Cl-. Da bi se temu problemu izognili, lahko sadimo križane tolerantne rastline, se poslužimo finančno zahtevnega razsoljevanja tal ali pa lahko rastline cepimo na tolerantno podlago in s tem izboljšamo ter povečamo pridelek in hkrati izkoristimo obdelovalno površino s povečano koncentracijo soli.Pumpkins are widespread and popular fruits that need plenty of water. Cultivation in arid and semi-arid areas requires irrigation. Due to the low precipitation and strong evapotranspiration, the salt concentrations in the soil can greatly increase. The lack of drinking water only increases the problem of saline soils, as producers are forced to irrigate with water, which has a high concentration of NaCl and other salts. Due to the requirements of the market for large and high-quality crops, every cultivable land should be used, and therefore pumpkins often grow on the ground with a increased salt concentration. In general, pumpkins are tolerant to saline stress, but their tolerance varies. For example, for cucumbers, lose up to 50% of the crop in salt salinity, expressed as electroconductivity (EC), of 6,3 dS / m, the zucchini have the loss at 7.9 dS / mWatermelons alredy lose half of the crop at 4.5 dS / m. The consequences of cultivating plants on saline soils are: impeded water acceptance in seeds when, due to higher osmotic potential, growth media cause toxicity that changes the activity of enzymes of nucleic acid metabolism, changes protein metabolism, disturbs the hormonal balance and reduces the utilization of seed stock. Increased salt absorption results in the toxic effects of Na+, Cl- or sulphate (SO42-) which reduce the acceptance of essential minerals such as nitrogen (N), phosphorus (P) and potassium (K) and calcium (Ca2+), as well as increased Na+ and Cl- in the leaves of plantsreduction of photosynthetic pigments, as photosynthesis decreases when high concentrations of Na+ and Cl- accumulate in chloroplasts and chlorophyl. In order to avoid this problem, we can plant crossbreeded tolerant plants, use a financially demanding desalination of the soil, or we can graft plants onto a tolerant roothstocks, thereby improving and increasing the yield, while also utilizing the working surface with increased salt concentration