This study aimed to assess the morphological and physio-biochemical responses of a commercial watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) cv. ‘Crimson Sweet’ grafted onto a drought-tolerant rootstock of wild watermelon (bitter apple, Citrullus colocynthis (L.) Schrad, ‘Esfahan’) in comparison with an ungrafted ‘Crimson Sweet’ watermelon or one grafted onto a commercial interspecific Cucurbita hybrid (Cucurbita maxima Duch. × Cucurbita moschata Duch.) rootstock (‘Shintoza’) under water stress. The experiment was conducted in pots under a controlled environment in a greenhouse, and water stress was imposed by maintaining moisture level in pots at 100% (well water (WW)) or 50% (water deficit (WD)) of container capacity (CC). WD significantly decreased most of the morphological traits in ungrafted and grafted plants, while the decrease in growth traits was lower in grafted plants than ungrafted plants. The response of grafted plants onto wild watermelon rootstock (‘Esfahan’) for most of the affected parameters (shoot fresh and dry weight, vine length and internodal length) was, however, comparable to those grafted onto commercial Cucurbita hybrid rootstock (‘Shintoza’). Plants grafted onto bitter apple (wild watermelon) exhibited a relatively lower decrease in growth and biomass, besides showing higher antioxidant activity (e.g., guaiacol peroxidase) concomitant with the lower accumulation of malondialdehyde and electrolyte leakage in the leaf tissues in comparison with ungrafted plants. The overall growth performance, as well as those under water stress conditions in commercial rootstock-grafted watermelon, was related to its better plant water status (e.g., high relative water content) which was likely ascertained by its greater root efficiency. This suggests that watermelons grafted onto bitter apple rootstock and Cucurbita hybrid rootstock were constitutively more resistant to drought, with higher efficiency in mitigating oxidative stress than ungrafted treatment. The above findings demonstrated that bitter apple, a well-adapted desert species, can be used as an alternative rootstock to commercial rootstocks (e.g., ‘Shintoza’) for watermelon grafting under water stress conditions. In addition, bitter apple rootstock can be involved in rootstock breeding programs to improve drought tolerance in watermelon.

Background: Medicinal plants, such as Ajuga chamaecistus Ging. ex Benth. are a natural and available source of treatment for a wide range of diseases. The objective of the present study was to assess the morphological and biochemical variation of 70 accessions of this species collected from seven geographical areas of Markazi province in the center of Iran. Results: The measured traits exhibited considerable variability across the populations. Positive correlations were observed between antioxidant activity and total phenolic content, as well as total flavonoid content. Principal component analysis showed six components explaining 72.15% of the total variance, and the PC1 explained 20.68% of the total variance. The Ward dendrogram based on morphological variables identified two main clusters. Morphological analysis of A. chamaecistus showed a high variation between qualitative and quantitative traits that help the breeders for selecting the desired genotypes. The accessions collected from the Robat-Mil area showed the highest values for the recorded morphological characteristics. Also, the populations of Robat-Mil, Hassanabad, and Khaneh-Miran were characterized by high values of total phenolic content, total flavonoid content, and antioxidant activity, which can be used in various industries, including pharmaceuticals, cosmetics, and food. Conclusions: Overall, the present results showed that the best place for the growth of A. chamaecistus with the production of significant contents of phenol and flavonoid is in Robat-Mil area.

This study investigated the effects of grafting cucumber (Cucumis sativus L. cv. Saba hybrid) onto a commercial Cobalt rootstock (Cucurbita maxima × Cucurbita moschata) and a local pumpkin (Cucurbita moschata) landrace from Zanjan province (named Zanjan) on plant growth, yield, and postharvest fruit quality. The study was conducted in a greenhouse using a completely randomized design with four replications. Various quantitative and qualitative indices were measured in grafted and non-grafted plants and subsequently, the data were analyzed using ANOVA followed by Tukey's HSD test (p ≤ 0.05). Relative to non-grafted plants, grafting response varied with respect to the rootstocks. Grafting onto Cobalt rootstock significantly increased chlorophyll content (from 1.22 to 1.69 mg g^-1 FW; + 39.0%), plant height (from 392.3 to 429.0 cm; + 9.4%), fruit number (from 35.5 to 54.8 fruits per plant; + 54.4%) and total yield (from 2.46 to 3.89 kg per plant; +57.9%), while reducing postharvest weight loss (17.6%) and firmness decline (39.2%). However total soluble solids measured at post-storage did not followe same trends and were highest in the local Zanjan rootstock-grafted plants, indicating variable postharvest responses with respect to the rootstocks. Although the Zanjan rootstock showed a significant increase in root volume (20.6%), it was not superior to the commercial rootstock for most yield-related traits. In contrast, leaf size and sensory quality were reduced in both rootstock-grafted plants; however, the flavor of the fruits remained within an acceptable range for consumers. Overall, the Cobalt rootstock-grafted plants demonstrated a more favorable balance between yield improvement and postharvest performance, therefore, cucumber grafting onto commercial rootstocks (i.e., Cobalt) can be considered a useful strategy to enhance the yield and postharvest quality of greenhouse cucumbers.

Considering the destructive effects of alkalinity stress on plants and the important role of silicon in stress alleviation, this study investigated the effects of foliar-applied silicon dioxide nanoparticles (SiO₂-NPs) at 0, 2, and 4 mM, under alkalinity stress induced by NaHCO₃ at 0, 5, 15, and 30 mM, on hydroponically grown potato ( Solanum tuberosum L. cv. Agria). Under non-stress conditions, SiO₂-NPs, particularly at 4 mM (N4), significantly enhanced plant growth, increasing plant length (8.5%), dry weight (15.3%) and root biomass (up to 38.6%) compared to the control (N0). Alkalinity stress alone exhibited a dose-dependent detrimental effect, severely suppressing growth parameters by up to 65% at 30 mM NaHCO₃. Importantly, SiO₂ nanoparticles significantly interacted with stress and provided a strong protective effect. This protective role extended to mini-tuber yield, where N4 maintained higher productivity under moderate and severe stress. Biochemically, SiO₂-NPs enhanced the antioxidant defense system, elevating carotenoids, total phenolics and flavonoids. Nanoparticles also preserved chlorophyll content and significantly reduced the depletion of mineral ions under stress conditions. The 4 mM SiO₂-NP treatment reduced the severe loss of key nutrients and retained magnesium (21.0%), iron (31.6%), potassium (33.2%) and calcium (42.6%) compared to the untreated control under high alkalinity conditions. The results demonstrate that foliar application of SiO₂-NPs, especially at 4 mM, increases alkalinity tolerance in potato plants by improving growth, antioxidant activity and nutrient uptake. Also, 5 mM NaHCO₃ acted as a beneficial root carbon source and showed a slight increase in some parameters compared to non-stress conditions. These results provide a suitable strategy for sustainable seed potato production in soilless systems with alkaline water.

Grafting and foliar calcium application are common practices for improving vegetable crops, but their interactions in soil and soilless cultivation systems are not well understood. To address these knowledge gaps for sustainable greenhouse cucumber production, this study investigated the effects of calcium foliar application (control, 200 mg/L as nano-CaCO₃ or CaCl₂) and grafting (no grafting, grafting on Ganate rootstock or Routpower rootstock) on the growth and yield of greenhouse cucumber cv. Saba in soil and soilless systems. It should be noted that the two cultivation systems differed in several management factors (pot size, substrate, irrigation frequency, and fertilization method), and this study compares complete production packages rather than isolating individual factors. The experiment was conducted in a greenhouse using a factorial design with four replications. The results showed that the cultivation system was the dominant factor. Soilless cultivation significantly increased shoot fresh weight (307–344 g), plant height (265–326 cm), number of fruits (36–54 per plant), and fruit yield (2.7–4.5 kg per plant) compared to soil cultivation (shoot fresh weight: 177–216 g; yield: 0.4–1.0 kg per plant). Conversely, plants grown in soil had higher leaf dry weight percentage, root dry weight percentage, chlorophyll, and carotenoids. The effects of grafting were system dependent, with non-grafted plants performing as well or better in soilless culture, while grafted plants (especially Saba/Routpower combination) showed some soil-based advantages, including greater root length. Foliar calcium did not significantly improve most parameters, indicating that standard nutrient management provided sufficient calcium or that the 200 mg/L concentration was insufficient. Under the conditions tested, ungrafted plants grown without foliar calcium supplementation in soilless culture achieved yields comparable to more complex treatments, suggesting a simpler and more cost-effective production strategy.