Environment, Photosynthesis, and Adventitious Rooting of Manchurian Lilac Cuttings Propagated in Overhead Mist, Submist, and Combination Systems

Abstract

<jats:p>We propagated manchurian lilac (<jats:italic>Syringa pubescens</jats:italic> subsp. <jats:italic>patula</jats:italic> ‘Miss Kim’) vegetatively from stem cuttings using overhead mist, submist, and combination propagation systems. Cuttings were collected when terminal buds were already set, after the period of tender growth that is optimal for lilac propagation. Net photosynthesis (P<jats:sub>n</jats:sub>) was recorded to assess whether differences in rooting could be attributed to differences in photosynthetic activity of cuttings within each system. The propagation environment differed significantly among systems, with vapor pressure deficit (VPD) substantially greater for submist systems than for overhead mist or combination systems, and root zones warmer in submist and combination systems than in overhead mist. P<jats:sub>n</jats:sub> of cuttings did not differ among systems and was initially low, but increased about when the first root primordia were visible. Rooting percentages were 90% among cuttings in the combination system, with cuttings in overhead mist and submist rooting at lower, but similar, percentages (68% and 62%, respectively). Cuttings in the combination and submist systems produced significantly more and longer roots than those in the overhead mist system, and retained nearly all of their leaves. Overall, the use of systems that provide intermittent mist to the basal end of each cutting was effective for propagating manchurian lilac. Our results demonstrate that cuttings in submist alone experience a much greater VPD than those in overhead mist, but may nonetheless root at comparable percentages and produce superior measures of root system quality. Combination systems show promise for rooting of species like manchurian lilac, because cuttings rooted at high percentages and with consistent root system quality, despite having been collected after the optimal spring period for lilac propagation.</jats:p>

Overcoming Physiological Bottlenecks of Leaf Vitality and Root Development in Cuttings: A Systemic Perspective

“…This highlights the need for future research on the underlying mechanisms and key factors in the plant-microorganism-abiotic environment continuum. More details about the modes of action of the distinct environmental inputs ( Figure 1 ) on cutting function consider also findings and concepts of Kadner and Druege (2004) , Husen and Pal (2007) , Rapaka et al (2008) , Bredmose and Nielsen (2009) , Agulló-Antón et al (2011) , Osterc and Stampar (2011) , Franken (2012) , da Costa et al (2013) , Bauerfeind et al (2015) , Rasmussen et al (2015) , Otiende et al (2017) , Zhang et al (2017) , Ferrari et al (2018) , Peterson et al (2018) , Taylor and Hoover (2018) , Cho et al (2019) , Heide (2019) , Sanchez et al (2020) and are summarized in Supplementary Table S1 .…”

Propagation of Five Species in a Commercial-scale Submist System

“…tem cuttings are traditionally propagated using overhead mist systems. Recent work has explored the use of a different approach: submist propagation (Peterson et al, 2018a(Peterson et al, , 2018bSanchez et al, 2020). Submist propagation systems apply water to the basal portions of cutting stems, rather than overhead.…”

“…Cuttings are suspended in an enclosure that contains a manifold of mist nozzles. Plants propagated in this system may have superior rooting compared with those propagated in overhead mist (Peterson et al, 2018a(Peterson et al, , 2018bSanchez et al, 2020). After propagation, cuttings are transplanted into soilless media, and their growth is similar to that of plants propagated in overhead mist (Peterson et al, 2018a(Peterson et al, , 2018b.…”

“…Submist propagation systems are a relatively new concept in commercial operations. Previous research with these systems has been conducted on small-scale, custom-built submist units that are unsuited to commercial propagation because they hold few cuttings (Peterson et al, 2018a(Peterson et al, , 2018bSanchez et al, 2020). For the industry to adopt submist propagation, larger systems must be designed that can effectively hold the greater number of cuttings propagated at commercial greenhouses or nurseries.…”

“…In previous research, manchurian lilac (Syringa pubescens ssp. patula 'Miss Kim') had more roots and longer roots when it was propagated in submist (Sanchez et al, 2020). Manchurian lilac plants are often challenging to propagate if cuttings are not taken at the right time (Hartmann et al, 2002) these challenging species form roots more reliably or quickly in submist.…”