Research paper
Samaneh Samavat; Mahdiyeh Salehi Vozhdehnazari
Abstract
Besides plant strategies to mitigate drought stress effects, the application of beneficial rhizobacteria may enhance plant tolerance. This study aimed to assess the ability of phosphate-solubilizing bacteria (PSB) to improve the growth and physiology of Achillea santolina (Santalin yarrow) under drought ...
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Besides plant strategies to mitigate drought stress effects, the application of beneficial rhizobacteria may enhance plant tolerance. This study aimed to assess the ability of phosphate-solubilizing bacteria (PSB) to improve the growth and physiology of Achillea santolina (Santalin yarrow) under drought stress. The interaction effects of PSB (Pseudomonas fluorescens isolates FRPF4, FRPF6, and FRPF12) (at 107 CFU/ml) and drought stress (30, 50, and 80% field capacity) were studied as a factorial test based on a completely randomized design under greenhouse conditions (n=3; P<0.05). Several vegetative and physiological parameters were measured at the full flowering stage. The growth factors included plant shoot height, canopy diameter, root length, and wet and dry weights. The results revealed a significant decrease in all the growth parameters under drought stress. However, PSB isolates, especially FRPF4, significantly moderated the stress negative effects on vegetative factors. Drought stress also significantly increased the total soluble sugars (TSS), free proline, total flavonoids (TF), and DPPH contents of the Santalin yarrow leaves. Drought-stressed plants inoculated with the PSB isolates showed a significant reduction in free proline and DPPH concentrations. However, the TSS and TF contents elevated in the stressed plants treated with PSB isolates. Carotenoid, chlorophyll a, b, and total chlorophyll contents also decreased in the stressed plants. However, the levels of these factors increased in the plants treated with PSB isolates in response to water deficit stress. Thus, PSB isolates may mitigate the adverse effects of drought stress on Santalin yarrow plants through several direct and indirect mechanisms.
Research paper
Dakshina YADAV; AMIT YADAV
Abstract
Nutrient resorption is a process of nutrient remobilization from senesced organs to living tissues inside a plant. Since the Northern Territory (NT) has relatively poor soil conditions and a limited supply of nutrients for plants, it is crucial to determine the suitable scion for efficient macronutrient ...
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Nutrient resorption is a process of nutrient remobilization from senesced organs to living tissues inside a plant. Since the Northern Territory (NT) has relatively poor soil conditions and a limited supply of nutrients for plants, it is crucial to determine the suitable scion for efficient macronutrient resorption in the Kensington Pride (KP) mango rootstock. The scions used in this study were NMBP 1201(T1), NMBP 1243 (T2), NMBP 4069 (T3), B74 (T4), and KP (T5). The experiment was laid out in a randomised, complete block design with five treatments and five replicates. The results showed that grafting B74 scion onto KP rootstock resulted in trees with reduced canopy area (65.76 ± 4.39b) and volume (48.43 ± 4.92b), indicating that it is suited for growing with a narrow planting distance to produce more mangoes in a smaller area. Grafting the B74 scion onto KP resulted in a larger leaf area (6.52 ± 1.36), ultimately increasing nutrient resorption efficiency, which is beneficial in nutrient-deficient soil like in the NT. NMBP 4069 scion grafted onto KP rootstock had a larger canopy area (87.47 ± 5.37a) and canopy volume (72.23 ± 6.21a). These trees will need more space to grow and have reduced nutrient resorption efficiency due to the smaller leaf area. The scions NMBP 1201 and NMBP 1243 displayed comparable growth metrics and nutrient resorption efficiency when grafted onto KP. The scion B74 is the most suitable variety to withstand diverse environmental conditions, optimise nutrient use, and increase fruit yield on a commercial level.
