مطالعه تاثیر تنش کادمیم بر صفات رویشی و میزان تجمع این فلز تحت کشت خالص و مخلوط ذرت (.zea mays l) و سویا (.glycine max l)

به‌‌منظور ارزیابی اثر کادمیم بر برخی از صفات ذرت (zea mays l.) و سویا (glycine max l.) در کشت خالص و مخلوط، آزمایشی در گلخانه دانشگاه علوم کشاورزی و منابع طبیعی ساری به‌صورت فاکتوریل در قالب طرح کاملا تصادفی با چهار تکرار اجرا شد. فاکتور اول غلظت‌های کادمیم شامل 0، 50، 100، 150 و 200 میلی‌گرم کادمیم در کیلوگرم خاک بود. فاکتور دوم نسبت‌های کشت ذرت و سویا (ذرت  در کشت خالص، سویا  در کشت خالص، ذرت در کشت مخلوط و سویا  در کشت مخلوط) بود. بذرها در گلدان‌های پنج کیلوگرمی کشت شدند و تراکم چهار بوته در گلدان در نظر گرفته شد و دو ماه پس از کشت بذر،  بوته‌ها برداشت شدند. نتایج بدست آمده نشان داد که غلظت کادمیم شاخساره ذرت در هر دو سیستم کشت مخلوط و منفرد بیشتر از سویا بود و کشت مخلوط به‌ویژه در سطوح بالا باعث افزایش غلظت کادمیم در شاخساره ذرت و سویا شد. همچنین با افزایش غلظت کادمیم در خاک، غلظت این عنصر در ریشه به‌طور خطی در تمامی سیستم‌های کشت افزایش یافت. ذرت نسبت به سویا در جذب و انباشت کادمیم در ریشه توانایی بیشتری داشت. همچنین کشت مخلوط ذرت و سویا باعث افزایش غلظت کادمیم در ریشه این گیاهان شد. به طوری که بیشترین غلظت کادمیم ریشه در کشت مخلوط برای گیاهان ذرت و سویا به‌ترتیب 105.97 و 60.46 میلی‌گرم در کیلوگرم ماده خشک ثبت شد. وزن خشک ذرت و سویا در کشت مخلوط نسبت به کشت خالص کمتر بود که به‌نظر می رسد جذب بیشتر کادمیم در اندام‌های این گیاهان عامل اصلی این موضوع باشد.

study of the effect of different concentrations of cadmium on vegetative traits and the rate of accumulation of this metal in mixed and monoculture of maize (zea mays l.) and soybean (glycine max l.)

introductioncadmium (cd) is the most mobile heavy element in the soil. this element in plants has a negative effect on the main function of the plant such as photosynthesis, cell proliferation, and water uptake by plant roots. resistance adaptation of some plants allows them to store high concentrations of heavy metals in their tissues without symptoms of poisoning, which eliminates them and revitalizes the environment. corn (zea mays l.) is able to continuously extract metals from contaminated soils by transferring them from roots to shoots. corn was also a promising crop for phytoremediation due to its extensive root system, high biomass, and compatibility with cadmium soils. also, legumes such as soybeans (glycine max l.) can accumulate heavy metals in their tissue, and their interaction with b. japonicum is an important aspect influencing the behavior of soybeans under heavy metal stress. mixed culture is a common cropping method that increases biomass. the use of this method in plants intended for plant extraction is of great importance because in contaminated soils it affects the uptake of heavy elements by plants. therefore, due to the importance of soil contamination with heavy elements, this study was designed to investigate the effect of mono and mixed corn and soybean culture on cadmium contaminated soil.materials and methodsthis experiment was performed in the greenhouse of sari agricultural sciences and natural resources university as a factorial in a completely randomized design with four replications. the first factor of cadmium concentrations was 0, 50, 100, 150 and 200 mg kg-1. the second factor was corn and soybean cultivation ratios (maize in pure cultivation, soybean in pure cultivation, corn in mixed cultivation and soybean in mixed cultivation with a ratio of 50: 50). the seeds were planted in 5 kg pots. the density was four plants in the pot was considered. two months after sowing, the plants were harvested. pre-harvest measurement traits included plant height and stem diameter and post-harvest measurement traits included shoot dry weight, root dry weight, cadmium concentration of shoot and root, and cadmium concentration in soil.results and discussionthe results showed that the concentration of cadmium in maize shoots in both mono-culture and mixed culture systems was higher than soybean and mixed cultivation, especially at high levels, increased the concentration of cadmium in maize and soybean shoots. also, with increasing the levels of heavy metal, the concentrations of cadmium in the roots increased linearly in all culture systems. maize had more ability to uptake and concentrate metals in its roots than soybeans, and mixed cultivation of maize and soybeans increased the concentration of cadmium in the roots of maize and soybeans. in this experiment. the highest concentrations of root cadmium in mixed maize and soybean crops were recorded 105.97 and 60.46 mg kg-1, respectively.conclusiondry weight of maize and soybeans was lower in mixed than pure cultivation, which seems to be the main cause of the higher uptake of cadmium in plant organs under mixed culture conditions. in general, the ability of maize to phytoextraction is higher than soybeans due to its higher biomass.