Morphological and germination response variability in seeds of wild yellow gentian (Gentiana lutea L.) accessions from northwest Spain

Abstract

Gentiana lútea L. (yellow gentian, Gentianaceae) is an important medicinal plant under protection as endangered species in most European countries. The aim of this work was to evalúate variation in seed mass, seed water content, and seed germination among 56 wild accessions of G. lútea. The effect of gibberellic acid (GA3), putrescine, moist chilling, and level of ripeness of seeds on subsequent germination was also investigated. Seeds of G. lútea showed physiological dormancy (final germination percentages ranged from 0% to 11%, depending on the accession) and GA3 enhanced seed germination drastically in all the accessions. The highest germination (99%) of GA3-treated seeds was reached at 15 °C. Final germination percentage and germination rate (as expressed by mean germination time), as well as seed mass and seed water content, varied significantly among accessions. In general, 1 year moist chilling did not significantly enhance G lútea seed germination. For most accessions, no significant differences were found between fully ripe seeds and less ripe seeds for seed water content, seed mass, and seed germination. Applications of GA3 were always most effective than those of putrescine for increasing seed germination.Key words: Gentiana lútea, gibberellic acid, physiological dormancy, putrescine, seed germination.Resume : Le Gentiana lútea L. (gentiane jaune, Gentinaceae) constitue une importante plante medicínale protégée en tant qu'espéce menacée, dans la plupart des pays d'Europe. Les auteurs ont cherché a évaluer la variation du poids des graines et la germination des graines au sein de 56 accessions du G. lútea. lis ont également examiné les effets de l'acide gibbérel-lique (GA3), de la putrescine, du froid humide, et du degré de maturité des graines sur la germination subséquente. Les graines du G lútea montrent une dormance physiologique (le pourcentage final de germination allant de 0% a 11 %, selon 1'accession) et la GA3 stimule fortement la germination chez toutes les accessions. On a obtenu le plus fort taux de germination a 15 °C avec des graines traitées par la GA3. Le pourcentage final de germination et le taux de germination (exprimé par le temps moyen de germination), ainsi que le poids des graines et leur teneur en eau, varient significativement selon les accessions. En general, 1 année de froid humide n'augmente pas significativement la germination des graines du G lútea. Chez la plupart des accessions, on n'observe aucune différence significative entre les graines pleinement matures, et les graines moins mures, quant a la teneur en eau ainsi que le poids et la germination des graines. Les applications de la GA3 demeurent toujours plus efficaces que celles de la putrescine pour augmenter la germination des graines.

The effect of pollination mode on seed performance of Gentiana lutea: a laboratory evaluation of seed germinability

“…symphyandra (Mt Grande population). These results are consistent with those obtained in previous studies with comparable protocols (Pérez‐García et al , González‐López and Casquero ), supporting the reliability of the method with regard to GA 3 concentration and germination temperature, and confirming its effectiveness as a successful treatment to enhance seed germination. As in most mountain plants, G. lutea seeds exhibit dormancy which can be overcome by means of cold treatments or gibberellic acid application.…”

“…Filter paper was divided into sectors; each sector was exclusively assigned to seeds resulting from a single capsule. Pérez‐García et al () showed that seeds of G. lutea treated with GA 3 reached comparable germination performances independently from darkness or photoperiod, while they found a decrease of germination at 25°C. In our study, dishes (n = 63) containing up to 60 seeds were randomly placed inside a climatic chamber and kept in the darkness at 17–19°C.…”

“…As most alpine plants, members of Gentianaceae exhibit seed dormancy (Baskin and Baskin , Schwienbacher et al ), though high variation of germination patterns may be observed among mountain species (Giménez‐Benavides et al ). According to Pérez‐García et al (), seeds of G. lutea show a non‐deep physiological dormancy, while Baskin and Baskin () described a non‐deep complex morphophysiological dormancy. Although in many species of Gentianaceae seed germination is difficult to achieve under laboratory conditions (Baskin and Baskin ), different techniques may be useful to surpass seed dormancy.…”

“…Cold stratification and pre‐treatment with gibberellic acid (GA 3 ) may help to overcome dormancy in several Gentiana species and improve seed germination (Struwe and Albert ), even though high concentrations may have inhibitory effects (Mikula and Rybczyńsky ). In particular, Pérez‐García et al () and González‐López and Casquero () reported that GA 3 may efficiently increase germination in seeds of G. lutea under different temperatures (from 15 to 20°C).…”

Seed germination of Phillyrea angustifolia L., a species of difficult propagation

“…Intraspecific variation in seed response to GA3 also could explain that while our data show that GA3 is detrimental to seed germination, previous results indicated that GA3 allowed high germination (Mira et al, 2015b). Intraspecific variation has been interpreted as one of the most important survival strategies for species growing under variable and unpredictable environmental conditions, as in Mediterranean forests, either in germination requirements (Kigel, 1995;Baskin & Baskin, 2014), seed dormancy (Pérez-García et al, 2012;Copete et al, 2014) or seed longevity (Lazar et al, 2014;Mira et al, 2011aMira et al, , 2011bMira et al, , 2015a.…”