Panupon Hongpakdee

The pathogenic fungus Sclerotium rolfsii is a major causal agent of tuber rot disease in Sunchoke (Helianthus tuberosus), resulting in significant yield losses. Therefore, this study aimed at investigating the antifungal activity of endophytic fungi isolated from medicinal plants against Sclerotium rot disease in sunchoke tubers. In addition, proteomic and metabolomic profiling of a selected endophytic fungus was performed. A total of 12 endophytic fungal isolates exhibiting antagonistic activity against S. rolfsii were obtained from 69 medicinal plant samples using the dual culture technique. Among these isolates, strain KKU-3.2, isolated from the root of Cratoxylum formosum, was selected and identified as a novel endophytic fungus, Diaporthe formosum sp. nov. Protein and metabolite profiling was performed using the selected strain D. formosum KKU-3.2. LC–MS-based proteomic analysis identified 32 proteins in the culture supernatant of the fungus. Furthermore, LC–MS-based metabolomic analysis detected 1600 metabolites, of which 24 were tentatively identified and selected as potential antifungal compounds based on previously reported activities or predicted functions. These tentatively identified metabolites were classified into eight chemical groups: coumarins, phenolic and organic acids, limonoids, depsides, pyrones and pyridines, flavonoids, sesquiterpenes, and indoles. Co-inoculation of D. formosum and S. rolfsii in sunchoke tubers demonstrated that D. formosum inhibited disease progression by 54.31%. This is the first report of D. formosum sp. nov. and, to the best of our knowledge, the first report describing the proteomic and metabolomic profiling of this novel species. The findings of this study provide a foundation for future research on the isolation and characterization of bioactive proteins and secondary metabolites, as well as their potential agricultural applications as biocontrol agents and biofertilizers.

This study consisted of two experiments examining the effects of nitrogen (N) forms on growth, flowering, photosystem II efficiency, tuber development, and nitrogen translocation in Jerusalem artichoke (Helianthus tuberosus L.) clone No. 3 (cv. CN 52867), a high-flowering genotype for edible potted plant production. The first experiment used a completely randomized design with four treatments: N-free control, ammonium (NH₄⁺), nitrate (NO₃⁻), and combined NH₄⁺ + NO₃⁻. Results showed that combined N form significantly improved specific leaf area compared with NO₃⁻, NH₄⁺, and the control. The combined treatment consistently produced the highest relative crop growth rate and nitrogen use efficiency across growth stages. It also increased leaf production, shoot and root biomass, and total dry matter. Flowering performance was enhanced under NO₃⁻ and combined N, with higher flowering percentage and larger flowers, while the combined treatment produced the highest flower number, petal number, and flower biomass. For tuber development, NO₃⁻ increased tuber number, whereas combined N produced larger tubers and the highest tuber fresh and dry weights. All N-supplied treatments improved chlorophyll fluorescence parameters (maximum quantum efficiency of photosystem II; Fv/Fm, electron transport rate; ETR, and photochemical quenching coefficient; qP). The second experiment, ¹⁵N tracer analysis, showed a clear shift in nitrogen allocation during development. Vegetative growth favored allocation to leaves and roots, and flowering promoted redistribution to reproductive organs, and pre-dormancy stages directed nitrogen mainly to newly formed tubers, indicating efficient internal recycling and storage. Overall, nitrogen form strongly influenced growth, reproduction, and sink allocation. Combined NO₃⁻ and NH₄⁺ supply optimized both ornamental quality and tuber yield, while ¹⁵N tracing clarified stage-dependent nitrogen dynamics, providing a physiological basis for improved nitrogen management in Jerusalem artichoke production.

Containerized ornamental plant production requires efficient irrigation strategies to balance plant quality with water and nutrient conservation. This study evaluated four leaching fraction (LF) levels (0%, 20%, 40%, and 60%) in a completely randomized design with three replications, each consisting of three pots, to determine their effects on plant growth, ornamental quality, gas exchange, water use efficiency (WUE), and macronutrient leaching in off-season potted Curcuma cv. ‘Jasmine Pink’. Irrigation volumes were determined using crop coefficient (Kc)-based estimates derived from evaporation pan measurements. The results showed that the highest LF level (60%) significantly improved several ornamental quality traits, including flower number per cluster, leaf greenness, specific leaf area, and compactness index, while also increasing aerial dry weight and improving gas exchange parameters during the flowering stage. These improvements were associated with reduced substrate electrical conductivity, indicating lower soluble salt accumulation in the root zone under higher LF treatments and more favorable conditions for plant growth. Leaching fraction is commonly used in containerized crop production to prevent excessive salt accumulation in the root zone by allowing excess irrigation water to drain from the substrate. However, increasing LF also resulted in greater irrigation water consumption and higher macronutrient losses through leachate, particularly potassium. In contrast, lower LF treatments (0–20%) improved water use efficiency and reduced nutrient losses but were associated with higher substrate electrical conductivity, suggesting greater soluble salt accumulation in the root zone. Overall, the results indicate that a higher LF (60%) provided the greatest improvement in plant growth and ornamental quality under the conditions of the present study for off-season potted Curcuma alismatifolia production, although integrated strategies may be required to reduce water and nutrient losses. These findings provide practical insights for optimizing irrigation management in container-grown ornamental crops.

Containerized ornamental plant production requires efficient irrigation strategies to balance plant quality with water and nutrient conservation. This study evaluated the effects of different leaching fraction (LF) levels (0%, 20%, 40%, and 60%) on plant growth, ornamental quality, water use, and macronutrient leaching in off-season potted Curcuma cv. ‘Jasmine Pink’. Irrigation volumes were determined using crop coefficient (Kc)-based estimates derived from evaporation pan measurements. The results showed that the highest LF level (60%) significantly improved several ornamental quality traits, including flower number per cluster, leaf greenness, specific leaf area, and compactness index, while also increasing aerial dry weight and photosynthetic performance during the flowering stage. These improvements were associated with reduced substrate electrical conductivity, indicating that higher LF might effectively mitigated root-zone salt accumulation and promoted favorable physiological conditions for plant growth. However, increasing LF also resulted in greater irrigation water consumption and higher macronutrient losses through leachate, particularly for potassium. In contrast, lower LF treatments (0–20%) improved water use efficiency and reduced nutrient losses but showed moderate salt accumulation in the root zone, which slightly limited photosynthetic performance and ornamental development. Overall, the results indicate that a higher LF (60%) provides optimal plant growth and ornamental quality for off-season potted Curcuma production, although integrated strategies may be required to reduce water and nutrient losses. These findings provide practical insights for optimizing irrigation management in container-grown ornamental crops.

Curcuma spp. is a popular ornamental crop valued for its vibrant appearance and suitability for both regular and off-season production. As global emphasis on freshwater conservation increases and with a demand for compact potted plants, reducing water use while maintaining high aesthetic quality presents a key challenge for horticulturists. Potassium silicate (PS) has been proposed as a foliar spray to alleviate plant water stress. This study aimed to evaluate the effects of PS on growth, ornamental traits, and photosynthetic parameters of off-season potted Curcuma cv. ‘Jasmine Pink’ under deficit irrigation (DI). Plants were subjected to three treatments in a completely randomized design: 100% crop evapotranspiration (ETc), 50% ETc, and 50% ETc with 1000 ppm PS (weekly sprayed on leaves for 11 weeks). Both DI treatments (50% ETc and 50% ETc + PS) reduced plant height by 7.39% and 9.17%, leaf number by 16.99% and 7.03%, and total biomass by 21.13% and 20.58%, respectively, compared to 100% ETc. Notably, under DI, PS-treated plants maintained several parameters equivalent to the 100% ETc treatment, including flower bud emergence, blooming period, green bract number, effective quantum yield of PSII (ΔF/Fm′), and electron transport rate (ETR). In addition, PS application increased leaf area by 8.11% and compactness index by 9.80% relative to untreated plants. Photosynthetic rate, ΔF/Fm′, and ETR increased by 31.52%, 13.63%, and 9.93%, while non-photochemical quenching decreased by 16.51% under water-limited conditions. These findings demonstrate that integrating deficit irrigation with PS foliar application can enhance water use efficiency and maintain ornamental quality in off-season potted Curcuma, promoting sustainable water management in horticulture.

ISHS XII International Symposium on Flower Bulbs and Herbaceous Perennials Enhanced flowering of sacred lotus (Nelumbo nucifera Gaertn.) by extending the photoperiod with supplemental lighting techniques

ISHS I International Symposium on Tropical and Subtropical Ornamentals Coconut coir dust ratio affecting growth and flowering of potted petunia hybrids