بررسی راهکارهای غلبه بر شیشه‏ای شدن در گیاهان باززا شده از کشت بساک‏های خیار

شیشه‏ای شدن یکی از شایع‌ترین اختلالات فیزیولوژیکی در کشت درون شیشه‌ای است که در شرایط خاصی مانند رطوبت بالا، نور ناکافی، قند اضافی و نیترات ایجاد می‌شود. این اختلال سبب تغییرات آناتومیکی، ریخت‌شناسی، فیزیولوژیکی و متابولیکی در گیاهان می‌شود. در پژوهشی جهت تولید گیاهان هاپلوئیدی با کشت بساک‌های خیار، تعداد زیادی از گیاهان باززا شده به شیشه‏ای شدن دچار شدند و شرایط طبیعی خود را از دست دادند. پژوهش حاضر در مورد بررسی روش‌های مختلف مقابله با شیشه‏ای شدن در گیاهان باززا شده حاصل از کشت بساک‏های خیار است. هشت تیمار شامل کاهش میزان رطوبت نسبی درون ظروف کشت، کاهش تعداد دفعات واکشت، کاهش غلظت سیتوکینین‏ها، القاء ریشه در ریزنمونه‏های باززا شده، افزایش شدت نور، سرمادهی از کف و کاهش غلظت اجزای محیط کشت در سه تکرار در قالب طرح کامل تصادفی روی گیاهان باززا شده انجام شد. نتایج نشان دادند بین تیمارها تفاوت معنی‌داری در سطح 1% وجود دارد. ریشه‌دار کردن گیاهان به میزان 70%، کاهش غلظت سیتوکینین‌ها 35%، افزایش شدت نور 30%، کاهش دفعات واکشت به هر 21 روز 25%، کاهش رطوبت نسبی 20%، سرمادهی از کف 2% و تغییر غلظت اجزای محیط کشت 1% منجر به کاهش شیشه‏ای شدن شد. بنابراین به نظر می‏رسد که ممکن است استفاده از یک یا چند روش مذکور برای از بین بردن کامل شیشه‏ای شدن همیشه موثر نباشد و انتخاب روش مناسب به ژنوتیپ و گونه گیاهی وابسته است.

investigation of some strategies to overcome hyperhydration in cucumber regenerated plants from anthers

hyperhydration is one of the most common physiological disorders in vitro conditions, leading to specific anatomical, morphological, physiological, and metabolic alterations. this study examines various methods to combat hyperhydration in regenerated plants derived from cucumber anthers cultures. the experiments included reducing relative humidity in culture vessels, decreasing the frequency of subculturing, lowering cytokinin concentrations, inducing root formation, increasing light intensity, bottom cooling, and altering the concentration of culture medium components. all experiments were conducted in a completely randomized design with three replications. results indicated significant differences among treatments at the 1% level (p ≤ 0.01). root induction reduced hyperhydration by 70%, decreased cytokinin concentrations by 35%, increased light intensity by 30%, reduced subculture frequency to every 21 days by 25%, lowered relative humidity in culture vessels by 20%, bottom cooling by 2%, and altering the concentration of culture medium components by 1%. the findings suggested that the impact of one or multiple methods in mitigating hyperhydration may not always be consistent and depends on the genotype and plant species.  introductioncucumber, an important plant in horticulture, is widely studied for its biological processes, including sex determination and gene transfer. tissue culture techniques are crucial for various biotechnological studies but face challenges like hyperhydration, a prevalent physiological disorder in vitro cultivation. hyperhydration leads to anatomical, morphological, physiological, and metabolic disruptions, affecting plant quality and acclimatization. symptoms include altered cell structures, reduced chlorophyll, and compromised enzymatic activity. mitigating hyperhydration involves adjusting environmental conditions and hormonal treatments, although not all methods are universally effective, highlighting the need for species-specific approaches in addressing this issue. materials and methodsthe preliminary stages of the experiment and cucumber plant regeneration from anther culture were carried out based on asadi et al. (2018). after inducing regeneration, samples affected by hyperhydricity were separated from the other explants and placed in ms with 30 g/l sucrose and a ph of 5.75, according to table 1.the experiment used a completely randomized design with three replications (each culture flask as one replication). in this study, eight treatments reported in table 1 were investigated. after applying the treatments, the number of plants with altered status was counted and recorded. analysis of variance (anova) was used for statistical analysis, and the least significant difference (lsd) test was applied for comparing means. excel 2016 and spss 26 software were used for data analysis. table 1- different treatments to overcome the hyperhydricity in cucumbers regenerated plants by anther culture results and discussionthe experiment demonstrated significant differences among treatments used to control and improve hyperhydricity in regenerated cucumber plantlets at a 1% significance level (p ≤ 0.01). the comparison of means indicated that rooting was the most effective method for significantly improving plant health. increasing light intensity and reducing subculture frequency also played important roles in enhancing plant growth conditions. decreasing bap concentration and relative humidity inside the culture vessels also had positive effects. conversely, treatments such as bottom ventilation and altering other growth medium components did not show significant effects.two methods were employed to reduce relative humidity: increasing agar concentration and using containers with filter lids. these methods reduced hyperhydricity by approximately 10%, although no significant difference was observed from the control group. increasing the subculture frequency increased hyperhydricity, while reducing the frequency decreased hyperhydricity rates. high concentrations of bap contributed to increased hyperhydricity. regenerated plants from combinations of 3 and 4 mg/l bap with 0.05 mg/l naa showed a 30% improvement when transferred to the plant growth regulator-free medium. rooting with 0.2 mg/l iaa significantly reduced hyperhydricity by about 70%. increasing the light intensity to 50 µmol/m²/s reduced hyperhydricity in 30% of regenerated plants. however, bottom ventilation, while showing improvement in 2% of samples, did not significantly differ from the control. conclusionoverall, the results indicate that inducing rooting, precise regulation of growth regulators’ type and concentration, increasing light intensity, reducing subculture frequency, and lowering relative humidity inside the culture vessels can significantly improve hyperhydricity. however, bottom ventilation and altering other growth medium components did not significantly impact. these findings suggest that achieving complete elimination of hyperhydricity may require additional methods depending on the genotype and species of the plant, necessitating further research in this area.