The effect of compost and combination of compost and biochar application in soil bulk density of planting bed, seedling emergence rate and early growth of saffron ecotypes

Emergence of saffron buds is sensitive to soil compaction and structure. Soil bulk density is introduced as the most important index of soil physical quality. Accordingly, this study was done to evaluate the effect of compost and compost-biochar in planting bed on the emergence and early seedling growth of saffron ecotypes and its relationship to soil bulk density. Experimental treatments consisted of planting beds (without any organic amendment (control), incorporation of 20 t.ha-1 compost and 10 t.ha-1 compost+ 8 t.ha-1 biochar (cellulosic material of hardwood)) and different ecotypes of saffron (Bajestan, Estahban, Ferdows, Gonabad, Natanz, Qaen, Sarayan, Torbate-Heydarieh and Zarand). Data obtained from experiment were subjected to combined analysis of variance among planting beds based on randomized complete block design. The results showed that application of compost and compost+biochar, improved emergence of the main and lateral buds as well as leaf growth parameters compared to the control. Zarand, Torbate-Heydarieh and Estahban ecotypes responded differently to the planting bed types in terms of emergence percent and rate of main bud compared to other ecotypes. Considerable variation was observed among the ecotypes in terms of all studied parameters, which indicated the adaptability of ecotypes to climatic conditions of corm provenance. Generally, the Bajestan, Ferdows and Qaen ecotypes showed superiority in terms of leaf area and dry weight. Compost and compost-biochar significantly (12%) reduced the soil bulk density compared to the control. Linear regression analysis indicated that there was a negative relationship between soil bulk density and the studied parameters, and significant decrease in all parameters was observed with increasing of soil bulk density

Effect of saffron (Crocus sativus L.) corm provenance on its agro-morphological traits and bioactive compounds

A three-year field study was conducted to examine the variation in agronomic performance, apo-carotenoids content, bioactive compounds and antioxidant activity of saffron corms originating from nine different regions of Iran. Significant differences were observed in flower-related traits, corm characteristics, picrocrocin and safranal contents, total phenolic content (TPC), total flavonoid content (TFC) and radical-scavenging activity between saffron corms of different provenance. The largest differences were observed for the flower-related traits and corm properties. Hierarchical classification of the saffron corms of different provenance resulted in three main groups. One of the three groups (provenance: Ferdows, Sarayan, and Bajestan) had high underground and above ground yield potential and also produced significantly higher picrocrocin and TFC in comparison to the other groups. In contrary the group comprising corms from Zarand, Torbat, Natanz, and Estahban were characterized by the lowest agronomic performance, TFC as well as lowest antioxidant activity. The third group, consisting of corms from Gonabad and Qaen, represented medium levels of agronomic-related traits, and the highest TPC and antioxidant ability. These results were further explored and confirmed by principal component analysis (PCA). PCA revealed positive relationships between corm properties on the one hand and flower number and stigma yield on the other hand. No relation between agronomic related traits and quality features was observed. Furthermore, the results indicated a positive relationship between total flavonoid content and antioxidant capacity of saffron. These results can be used for the improvement of the yield and quality as well as in programs for selection of the most suitable corms for particular production locations.</p

Essential oil production, chemical composition, bioactive compounds, and antioxidant activity of <i>Thymus vulgaris</i> as affected by harvesting season and drying conditions

In this study, the effects of seven distinct were assessed in two harvesting seasons (spring and autumn) on the essential oil (EO) content, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and volatile compounds of thyme (Thymus vulgaris L.). The drying methods tested included sun-drying, shade-drying, freeze-drying (FD), oven drying at 40 °C (OV40) and 70 °C (OV70), and microwave 360 W (MW360) and 720 W (MW720). The analysis of essential oils facilitated the identification of numerous compounds, 18 of which accounted for approximately 64.94% to 67.84% of the total thyme EO compounds. Six significant compounds were investigated, including thymol, p-cymene, γ-terpinene, carvacrol, linalool, and borneol. The results demonstrated that the thyme samples harvested in spring possessed higher amounts of γ-terpinene, thymol, carvacrol, EO content, and TFC, while samples harvested in autumn exhibited the highest amounts of borneol, p-cymene, TPC, and higher antioxidant activity. Principal component analysis (PCA) findings revealed that thyme samples harvested in spring, dried in the sun, shade, and FD conditions were rich in EO content, γ-terpinene. The samples dried in MW720, OV40, and FD conditions possessed the highest amounts of thymol, carvacrol, and TFC. Drying the samples under MW360, OV40, and FD indicated significantly higher TPC and linalool. Drying the autumn-harvested samples under the sun and shade also exhibited higher linalool and TFC than other methods. Overall, the results conclusively indicated that the harvesting season and drying conditions significantly affected bioactive compounds, antioxidant activity, and EO production and quality. Such findings may add value to the product at the producers’ levels to produce more quality thyme depending on the harvesting season.</p

The possibility for improvement of flowering, corm properties, bioactive compounds, and antioxidant activity in saffron (Crocus sativus L.) by different nutritional regimes

Saffron as one of the most precious spices and medicinal plants, is highly valued for its bioactive compounds. Quantity and quality in spices and medicinal plants can be improved by the plant nutrition. In this field study the sole and integrated application of various fertilizers types and arbuscular-mycorrhizal fungus (AM), Glomus mosseae with respect to the flower-related traits, corm properties, quality, bioactive compounds and antioxidant activity of saffron at Kerman region, Iran was examined over a three years period. The fertilizer treatments comprised control (non-amended soil); 20 Mg ha −1 compost; 10 Mg ha −1 compost+ 8 Mg ha −1 biochar and chemical fertilizers. In each fertilizer treatment, planting bed was inoculated or non-inoculated with AM. The results showed that during the first flowering period (2015–16), neither AM nor fertilizer types affected flowering. Inoculation with AM particularly in the application of fertilizer treatments through positive effects on different corm properties during the vegetative growing seasons of 2015–16 and 2017–18, improved flower-related traits in the next flowering periods of 2016–17 and 2017–18. Picrocrocin and safranal content as well as total phenolic content and total flavonoid content in tepals were considerably enhanced by organic amendments and chemical fertilizers compared with the control. While the total phenolic content in stigmata was reduced by AM-inoculation, the total flavonoid content and antioxidant activity of stigmata and tepals were not significantly influenced. Principal Component Analysis clearly discriminated the integrated nutritional treatments from the sole ones based on flower-related traits and corm properties which were positively related with integrated treatments. Organic amendments were characterized by a higher total phenolic content and antioxidant activity in stigmata. Chemical fertilizers alone or in AM-inoculation associated with quality attributes and total flavonoid content in tepals. Research findings confirmed that the integrated application of mycorrhizal fungus, organic, and chemical fertilizers significantly influences the overall production of saffron. </p

Identification and characterisation of volatile fingerprints of saffron stigmas and petals using PTR-TOF-MS : Influence of nutritional treatments and corm provenance

This study investigated the effects of different agronomical practices of saffron on the volatile organic compounds (VOCs) of saffron stigmas and petals using proton transfer reaction-time of flight-mass spectrometry. Saffron flower samples treated with different nutritional treatments as well as samples of corms of different provenances were harvested from a three-year-old saffron field. The results revealed that 2(5H)-furanone, safranal, acetic acid, and isobutanal contributed mostly (more than 55% of the identified VOCs) to the volatile profile of the ground saffron stigmas samples. 2(5H)-Furanone, isobutanal, 2,3-butanedione, and acetic acid was likely responsible for the overall aroma of the petals, as it accounted for 67%, 7%, 5%, and 5% of the identified VOCs, respectively. Based on the mass spectral data measured, 2(5H)-furanone and safranal were not the dominant volatile compounds in the intact stigmas samples. In intact form, isobutanal, acetic acid, methanol, and acetone were the most abundant compounds. This finding must be considered in saffron-related analyses. The compounds that were the most abundant in the aroma profile of saffron were the same in both the conventionally and organically grown corms, in spite of some differences in intensities. In general, the organically grown samples presented a higher concentration in safranal, 2(5H)-furanone, phenol, and 1-t-butylcyclopentadiene, whereas acetaldehyde and isobutanal concentrations were higher in the saffron stigmas grown with mineral fertilizers. The organic nutritional treatments applied in this study may be useful for organic saffron producers to select treatments to achieve saffron with high quality. Variation in VOCs in petals and stigmas among corms originating from different regions verifies that the selection of the most suitable corms can be considered as an important factor affecting the quality of saffron.</p