Exogenous abscisic acid prolongs the dormancy of recalcitrant seed of Panax notoginseng

Abstract

The seeds of Panax notoginseng (Burk.) F. H. Chen are typically characterized by their recalcitrance and after-ripening process and exhibit a high water content at harvest as well as a high susceptibility to dehydration. Storage difficulty and the low germination of recalcitrant seeds of P. notoginseng are known to cause an obstacle to agricultural production. In this study, the ratio of embryo to endosperm (Em/En) in abscisic acid (ABA) treatments (1 mg·l−1 and 10 mg·l−1, LA and HA) was 53.64% and 52.34%, respectively, which were lower than those in control check (CK) (61.98%) at 30 days of the after-ripening process (DAR). A total of 83.67% of seeds germinated in the CK, 49% of seeds germinated in the LA treatment, and 37.33% of seeds germinated in the HA treatment at 60 DAR. The ABA, gibberellin (GA), and auxin (IAA) levels were increased in the HA treatment at 0 DAR, while the jasmonic acid (JA) levels were decreased. ABA, IAA, and JA were increased, but GA was decreased with HA treatment at 30 DAR. A total of 4,742, 16,531, and 890 differentially expressed genes (DEGs) were identified between the HA-treated and CK groups, respectively, along with obvious enrichment in the ABA-regulated plant hormone pathway and the mitogen-activated protein kinase (MAPK) signaling pathway. The expression of pyracbactin resistance-like (PYL) and SNF1-related protein kinase subfamily 2 (SnRK2s) increased in the ABA-treated groups, whereas the expression of type 2C protein phosphatase (PP2C) decreased, both of which are related to the ABA signaling pathway. As a result of the changes in expression of these genes, increased ABA signaling and suppressed GA signaling could inhibit the growth of the embryo and the expansion of developmental space. Furthermore, our results demonstrated that MAPK signaling cascades might be involved in the amplification of hormone signaling. Meanwhile, our study uncovered that the exogenous hormone ABA could inhibit embryonic development, promote dormancy, and delay germination in recalcitrant seeds. These findings reveal the critical role of ABA in regulating the dormancy of recalcitrant seeds, and thereby provide a new insight into recalcitrant seeds in agricultural production and storage.

Ascorbic acid releases dormancy and promotes germination by an integrated regulation of abscisic acid and gibberellin in Pyrus betulifolia seeds

“…The genes associated with ABA and GA play critical roles in the regulation of dormancy and germination of seeds. Wang et al (2023) found that increased ABA signalling and suppressed GA signalling inhibit the growth of the embryo and the expansion of developmental space. In the process of AsA to relieve seed dormancy and stimulate germination, the transcriptome data showed that there were 12 genes related to ABA and GA metabolism (Table 2).…”

“…Hence, AsA releases dormancy and promotes germination by modulating the signalling pathways of ABA and GA and the metabolic levels of ABA, GA, and the ABA/GA ratio. In addition, the changes in germination percentage and endogenous hormones demonstrated that the dormancy type of Pyrus betulifolia seeds belongs to physiological dormancy.The genes associated with ABA and GA play critical roles in the regulation of dormancy and germination of seeds Wang et al (2023). found that increased ABA signalling and suppressed GA signalling inhibit the growth of the embryo and the expansion of developmental space.…”

Endogenous Hormone Levels and Transcriptomic Analysis Reveal the Mechanisms of Bulbil Initiation in Pinellia ternata

“…Following the ABA treatment of Panax notoginseng seeds, the expressions of PYL and SnRK2s increased, whereas the expression of PP2C decreased. The expression of PP2C was positively correlated with the content of ABA [ 68 ]. In this study, we conclude that during P. ternata bulbil initiation, the ABA content increased, PP2C expression elevated, and SnRK2 expression decreased.…”

Analysis and Identification of Genes Associated with the Desiccation Sensitivity of Panax notoginseng Seeds

“…So, they have morphophysiological dormancy (MPD) [14]. Previous studies showed that exogenous gibberellic acid could shorten the after-ripening process, and abscisic acid could prolong the dormancy of the seed of P. notoginseng [16,17]. However, P. notoginseng seeds also have recalcitrant traits, such as not undergoing maturation drying, a high water content, high sensitivity to dehydration, and a short life span in natural conditions [15,18].…”