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Background: Dwarf rootstocks have important practical significance for high-density planting in pear orchards. The shoots of 'Cuiguan' grafted onto the dwarf rootstock were shorter than those grafted onto the vigorous rootstock. However, the mechanism of shorter shoot formation is not clear., Results: In this study, the current-year shoot transcriptomes and phytohormone contents of 'CG‒QA' ('Cuiguan' was grafted onto 'Quince A', and 'Hardy' was used as interstock) and 'CG‒DL' ('Cuiguan' was grafted onto 'Duli', and 'Hardy' was used as interstock) were compared. The transcriptome results showed that a total of 452 differentially expressed genes (DEGs) were identified, including 248 downregulated genes and 204 upregulated genes; the plant hormone signal transduction and zeatin biosynthesis pathways were significantly enriched in the top 20 KEGG enrichment terms. Abscisic acid (ABA) was the most abundant hormone in 'CG‒QA' and 'CG‒DL'; auxin and cytokinin (CTK) were the most diverse hormones; additionally, the contents of ABA, auxin, and CTK in 'CG‒DL' were higher than those in 'CG‒QA', while the fresh shoot of 'CG‒QA' accumulated more gibberellin (GA) and salicylic acid (SA). Metabolome and transcriptome co-analysis identified three key hormone-related DEGs, of which two (Aldehyde dehydrogenase gene ALDH3F1 and YUCCA2) were upregulated and one (Cytokinin oxidase/dehydrogenase gene CKX3) was downregulated., Conclusions: Based on the results of transcriptomic and metabolomic analysis, we found that auxin and CTK mainly regulated the shoot differences of 'CG-QA' and 'CG-DL', and other hormones such as ABA, GA, and SA synergistically regulated this process. Three hormone-related genes ALDH3F1, YUCCA2, and CKX3 were the key genes contributing to the difference in shoot growth between 'CG-QA' and 'CG-DL' pear. This research provides new insight into the molecular mechanism underlying shoot shortening after grafted onto dwarf rootstocks., (© 2024. The Author(s).)

Root traits are essential for optimising nutrient and water absorption and anchorage. However, changes in root traits and the contribution of root-to-shoot growth and development of soybean (Glycine max (L.) Merr.) across a century of breeding are poorly documented. In this study, we adopted a grafting technique, using 55 cultivars released in the three main soybean-production regions in China as rootstocks in a pot experiment and 24 cultivars from the Yellow-Huai-Hai Valley (YHH) region as rootstocks in a field experiment, with cv. Zigongdongdou as the common scion. Changes in soybean roots, including dry weight (DW) of roots, lateral root number (LRN) and taproot length (TRL), and their contribution to shoot development and biomass formation, including shoot DW, plant height and node number, were evaluated under optimal conditions in 2011. Aboveground traits declined with year of release in the YHH region and did not vary over time in the northern Heilongjiang province and mid-south Heilongjiang region except for shoot DW. The root traits root DW, LRN and TRL were similar over years of release in the pot and field experiments. The results suggest that the newer cultivars have lesser shoot growth and root capacity but the same amount of root growth as older cultivars. Root traits did not change during selection, suggesting that improvement in soybean root traits should be an aim in future breeding. We adopted a grafting technique using cultivars released from 1929–2006 in China as the rootstock and the cultivar Zigongdongdou as the common scion. We found that the aboveground traits declined with year of release of stock cultivar, while the measured root traits did not change significantly with year of release. This study established a method to study the intact root system and facilitates improvement of soybean root system. [ABSTRACT FROM AUTHOR]

Cynanchum bungei Decne is a rare, endemic, and important medicinal plant species in China. Seed germination and early seedling growth of large seeds (greater than 7 mm) and small seeds (smaller than 7 mm) were investigated at three temperatures (15, 20, and 25 °C) in both continuous light and alternating light/dark photoperiods to determine seed propagation requirements. Photoperiod significantly affected seed germination and early seedling growth. Germination and seedling growth at a 12:12-h photoperiod performed better than in continuous light. Temperature had a significant effect on germination index (GI), vigor index (VI), germination velocity (GV), mean germination time (MGT), shoot biomass (SB), root biomass (RB), and taproot length (TL), but no significant effect on final germination percentage (FGP). A temperature of 20 °C was the optimum temperature for seed germination and early seedling growth. Average growth height (AGH) and relative growth rate (RGR) of shoots at 15 °C were greater than that at 20 °C. Large seeds had better germination and seedling performance than small seeds. However, small-seeded seedlings had greater biomass allocated to roots (BAR) and root-to-seedling ratio (RSR) than seedlings from large seeds. Small seeds of C. bungei could be more competent in unfavorable soil and light conditions than large seeds. [ABSTRACT FROM AUTHOR]

Ginkgoalean leaves attributed to Ginkgoites myrioneurus sp. nov. and associated long and dwarf shoots were collected from the Lower Cretaceous coal-bearing Muling Formation of the Jixi Basin, eastern Heilongjiang, China. The common characteristic feature of the various leaves is the dense venation. The species may be distinguished from other known species of Ginkgoites from the Jurassic and Lower Cretaceous of eastern Asia in having 8–18 closely arranged oblanceolate segments each with 6–16 veins. The fragmentary long and dwarf shoots are similar to those of extant Ginkgo biloba in gross morphology. They are considered to belong to the same tree as that which produced Ginkgoites myrioneurus. [Copyright &y& Elsevier]