Anatomical, morphological and growth responses of Thinopyrum ponticum plants subjected to partial and complete submergence during early stages of development

Abstract

<jats:p> Seedling recruitment and growth of forage grasses in flood-prone grasslands is often impaired by submergence. We evaluate the responses of Thinopyrum ponticum (Podp.) Barkw. &amp;amp; Dewey to partial and complete submergence at two early stages of development. Two greenhouse experiments were carried out with plants at three expanded leaves (Experiment 1) or five expanded leaves stage (Experiment 2). In each case, three treatments were applied for 14 days: control (C), partial submergence (PS; water level to half plant height), and complete submergence (CS; water level to 1.5 times plant height). Submergence was followed by a recovery period of 14 days at well drained conditions. Assessments included plant survival, height, leaf blade and pseudostem length, soluble carbohydrates in pseudostem, and shoot and root dry mass accumulation at the beginning and end of the submergence, and at the end of the recovery period. Root aerenchyma formation was determined on day 14 in both experiments. Under PS all plants survived, and the impact of the stress was related to the plants’ developmental stage. However, plants with five expanded leaves increased total plant biomass with respect to control by 48%, plants with three expanded leaves reduced it by the same percentage. This response could be related to a higher ability to form root aerenchyma (17 vs 10%), and an enhanced leaf de-submergence capacity due to promoted leaf blade and pseudostem lengthening. Complete submergence treatment compromised the survival of 70% of the individuals with three expanded leaves but did not affect the survival at the five expanded leaves stage. In any developmental stage (three or five expanded leaves) plants fail to promote enough elongation of leaf blades or pseudostems to emerge from the water, so that always remained below the water surface. Root aerenchyma was not increased by CS at either of these two plant developmental stages. The high amount and concentration of pseudostem total soluble carbohydrates of the larger (five expanded leaves) plants facilitated their recovery growth after submergence. Our results predict the successful introduction of this species in areas where water excesses can cause soil waterlogging or shallow-partial plant submergence, but suggest avoidance of areas prone to suffer high-intensity flooding that lead to full plant submergence as this would highly constrain plant recruitment. </jats:p>

Response of endophyte‐infected and endophyte‐free tall fescue plants to partial submergence at two developmental stages

“…For this purpose, plants from five replicates were carefully dissected. Three root samples per plant were taken and preserved in formalin‐acetic alcohol until analysis (Iturralde Elortegui et al., 2020; Silva et al., 2003). Sections (15–20 mm) were cut about 20 mm from the root tip.…”

Functional responses to multiple sequential abiotic stress (waterlogging‐drought) in three woody taxa with different root systems and stress tolerance

“…At the end of the experiment, three fresh roots per plant were randomly taken from three individuals of each treatment and species for anatomical observations and measurements. They were cut out under water, washed with deionized water and preserved in formalin‐acetic alcohol (dilution 10:50:5:35 = formaldehyde:ethyl alcohol:glacial acetic acid:distilled water) until analysis (Iturralde Elortegui et al, 2020; Silva et al 2003). In the laboratory, sections (15–20 mm) were cut at around 30 mm from the root tip.…”

Halo‐hydromorphism alters nitrogen fertilization responses of tall wheatgrass pastures: Capture and use of resources, tiller dynamics and forage production

“…& Dewey) is a perennial grass that tolerates the typical stresses occurring in HHM environments (Jenkins et al., 2010). It thrives in environments with a wide range of soil and climatic constraints (Asay & Jensen, 1996; Mazzanti et al., 1992) and is mainly characterized by its high tolerance to salt and water stress, both deficit and excess (Bahrani et al., 2010; Borrajo et al., 2018; Iturralde Elortegui et al., 2020; Priano & Pilatti, 1989; Weimberg & Shannon, 1988). In addition, being a C 3 species, it can take advantage of the optimal autumn and spring growing conditions of the Humid Pampas region (14–22°C mean daily temperature, 14–22 Mj/m 2 /day of incident solar radiation and 700–1100 mm/year of rainfall; Hall et al., 1992).…”

“…Most research on the tolerance and responses of forage species to typical stresses of HHM environments (e.g., salinity and/or water stress) has been carried out under greenhouse or growth chamber conditions, with a focus on individual plants (Bahrani et al., 2010; Borrajo et al., 2018; Iturralde Elortegui et al., 2020; Menon‐Martínez et al., 2021; Priano & Pilatti, 1989; Weimberg & Shannon, 1988). Few studies analyse, under field conditions, the productive capacity of forage species in halo‐hydromorphic environments (Bertram et al., 2021; Jenkins et al., 2010).…”