Direct Seeding and Transplanting Influence Root Dynamics, Morpho-Physiology, Yield, and Head Quality of Globe Artichoke

Abstract

The objective of this two-year field study was to assess the influence of stand establishment methods (direct seeding or transplanting) on root growth dynamics, shoot morphology, leaf physiology, yield, and quality of globe artichoke (Cynara cardunculus). Three artichoke cultivars were evaluated, ‘Green Globe Improved’ (GGI), ‘Imperial Star’ (IS), and ‘Romolo’ (ROM). Plants established with the transplanting method had higher mean root length intensity (La), root length, and root surface area as compared to plants established by direct seeding. The topsoil (0–20 cm) had on average higher La, root length, and root surface area than deeper soil profiles. Transplanted plants had higher plant shoot width and leaf area index (LAI) chlorophyll content index (SPAD) than direct seeded plants at the vegetative stage in 2015. The improvement of root and shoot growth in transplants (compared to direct seeding) also resulted in higher (p < 0.05) marketable yield (21.1 vs. 19.9 ton ha−1 in 2015 and 18.3 vs. 13.7 ton ha−1 in 2016). Additionally, 46–50% of the total yield occurred during the first 30 days of harvest in the transplanting method compared to 13–38% for direct seeding. No significant differences were found between planting methods or cultivars in leaf-level gas exchange (photosynthesis, stomatal conductance, and transpiration) and cynarin concentration in the marketable heads. Although chlorogenic acid was similar in both establishment methods in 2015, direct seeding had higher concentration in 2016. Comparing cultivars, GGI had higher root length, surface area, root volume, and earlier and higher marketable yield than ROM. However, ROM had higher mean root length intensity (La; total root length per specific area in soil profile) than GGI in both growing seasons. This study showed significant and consistent improvements in root and shoot traits, and yield for transplants as compared to direct seeded plants.

Deep planting improved stem root growth, flower yield and quality of Lilium cultivars

“…The Royal FloraHolland which is one of the largest auction organizations in the world sold about 282 million lily flowers in 2019 (Statista, 2019). Cultural practices such as nutrient management, growing substrate selection and exogenous hormones application have significantly affected lily growth, physiology, and flower quality (Al-Ajlouni et al, 2017;A'saf et al, 2020;Othman et al, 2021). For example, using 0-4 mm tuff substrate improved growth and flower quality of Lilium × elegans (cvs.…”

“…Lily bulbs are grown in a wide range of soil or soilless media types including peat-moss, tuff and cocopeat (Al-Ajlouni et al, 2017;Othman et al, 2021). However, the addition of aggregates such as perlite to growing media is recommended to improve drainage and aeration.…”

“…Assessment of proper management practices to improve lily growth, flower quality and yield is not new. However, few studies have included leaf gas exchange analysis [photosynthesis (P n ), stomatal conductance (g s ) and transpiration (E)] as an aid to understand the leaf-level physiology of lily plants (Chang et al, 2008;Othman et al, 2021). In addition, no study we are aware of has assessed the effect of planting depth on stem roots and flower quality (color, diameter, number per plant) of lily cultivars.…”

“…Gas exchange was determined from two fully expanded sunny-exposed leaves with a portable photosynthesis system (LI-6400XT; LI-COR, Lincoln, NE, USA). Light intensity was set to track ambient photosynthetically active radiation, reference carbon dioxide to 400 μmol, flow rate to 500 μmol s -1 , and chamber head to 6 cm 2 (Leskovar & Othman, 2021). Following the commercial practices, harvesting stage was when one of the flowering buds began to open but not fully opened (Othman et al, 2021).…”

“…Light intensity was set to track ambient photosynthetically active radiation, reference carbon dioxide to 400 μmol, flow rate to 500 μmol s -1 , and chamber head to 6 cm 2 (Leskovar & Othman, 2021). Following the commercial practices, harvesting stage was when one of the flowering buds began to open but not fully opened (Othman et al, 2021). At harvesting stage, plant morphology (plant height, leaf area and stem diameter) was determined.…”