In order to explore the mechanism of delayed and uneven germination in sharp tooth oak (Quercus aliena var. acuteserrata) (STO), mechanical scarification techniques were used to study STO root and shoot germination and growth. The techniques used were: removing cup scar (RS), removing the pericarp (RP), and cutting off 1/2 (HC) and 2/3 (TC) cotyledons. Germination percentage and root and shoot length for Chinese cabbage (Beassica pekinensis) seeds (CCS) were also investigated for CCS cultivated in a Sanyo growth cabinet watered by distilled water and 80% methanol extracts from the acorn embryo, cotyledon and pericarp with concentrations of 1.0 g, 0.8 g, 0.6 g and 0.4 g dry acorn weight per ml methanol. The results showed that the majority of roots and shoots from acorns with RP and HC treatment emerged two weeks earlier, more simultaneously, and their total emergences were more than 46% and 28% higher, respectively. TC accelerated root and shoot emergence time and root length, but root and shoot germination rate and shoot height had no significant difference from the control. Positive consequences were not observed on all indices of RS treatment. The germination rates of CCS watered by 1.0 g·ml⁻¹ methanol extracts from the embryo and cotyledon were significantly lower than those from the pericarp, and all concentrations resulted in decreased growth of root and shoot. Methanol extracts from pericarp significantly reduced root length of CCS, but presented little response in germination percentage and shoot length. The inhibitory effect was gradually increased with the increasing concentration of the methanol extract. We conclude that both the mechanical restriction of the pericarp and the presence of germination inhibitors in the embryo, cotyledon and pericarp are the causes for delayed and asynchronous germination of STO acorns.

In this paper, we present the results of a study on the effects of exogenous antioxidant germanium (Ge) on seed germination and seedling growth, and its role as a radical scavenger that regulates related enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), under salt stress. Seeds were incubated in 0, 50, 100, 150, 200, 250 and 300 mM NaCl to determine the salt tolerance of the Lycium ruthenicum Murr seedlings and from the results, the critical and ultimate salt concentrations were chosen for the next experiment. Subsequently, two treatments (seeds soaked in Ge and Ge added to salt) with four concentrations of GeO₂ (0, 5, 10 and 20 μM) were used with the critical (150 mM) and ultimate salt concentrations (250 mM). The results demonstrated that salt alone inhibited seed germination significantly (≥150 mM) and reduced seedling growth (≥200 mM). The addition of exogenous Ge to the salt solution, as well as soaking the seeds in Ge, attenuated the salt stress effects in a manner dependent on the dose of Ge, as indicated by the increased percentage of seeds that germinated and improved seedling growth. The addition of Ge also showed a significant reversal of salt stress on the activities of antioxidant enzymes, with a decrease in SOD and POD activity, but an increase in CAT activity with 150 mM NaCl, and enhancement of SOD, POD and CAT with 250 mM NaCl. Correspondingly, the level of malondialdehyde was decreased significantly by each Ge treatment under salt stress. Further, for L. ruthenicum, adding 10 Ge and seeds soaked in 5 Ge were the most effective treatments. To our knowledge, this is the first report to show the protective effects of exogenous Ge against salt-induced oxidative damage in L. ruthenicum seed germination and seedling growth. Thus, L. ruthenicum can be used in areas with salty soil and Ge can promote the plants’ salt tolerance

Delayed and uneven germination of acorns has a negative effect on seedling quality and yield in seedlings. To address this issue, the effects of different mechanical treatments were studied, including a control (CK), removal of cup scar (RS), removal of pericarp (RP), removal of pericarp and 1/2 of the cotyledon (HC) and removal of pericarp and 2/3 cotyledon (TC), on the germination of Quercus variabilis, Q. wutaishanica and Q. robur acorns and pericarp thickness. The results showed that (1) RP and HC treatments significantly decreased root and shoot mean germination time, increased rooting and shooting germination percentage, and improved the root and shoot synchronization and vigor indexes of the three species’ acorns; (2) the acorns from the TC treatment significantly reduced root and shoot mean germination time and significantly induced the root and shoot synchronization index for all three species; and (3) the RS treatment significantly reduced the root and shoot mean germination time of the three species. Therefore, RP and HC treatments can effectively accelerate germination and regular seedling, which are important in the propagation of Q. variabilis, Q. wutaishanica and Q. robur seedlings. Even and quick germination help reduce acorn predation.

Nutrient loading in the fall is a practical way to improve seedling quality and has been proven to increase nutrient accumulation, translocation and utilization. Few studies have reported on the variation in free amino acids as a result of fall fertilization, especially for different seasonal needle habits (evergreen, deciduous). Therefore, a balanced two-factor factorial design with one fall fertilization treatment (10 mg N/seedling) and Chinese pine (Pinus tabulaeformis Carr.) and Prince Rupprecht’s larch (Larix principis-rupprechtii Mayr.) seedlings was used to examine growth response over one nursery season. Associated changes between fall fertilization, N storage and free amino acids were analyzed. Results showed that: (1) stem height, diameter and biomass for both species were similar between controls and fall fertilization treatments; (2) compared to controls, fall fertilization increased Chinese pine needle and root N by 17.7% and 36.9%, respectively. For Prince Rupprecht’s larch, fall fertilization resulted in 26.3% and 34.54% more N in stem and roots, respectively, than controls; (3) the three main amino acids in control and fertilization treatments in Prince Rupprecht’s larch seedlings were glutamine, arginine and proline, and in Chinese pine seedlings were glutamine, arginine and γ-amino butyric acid; (4) total amino acid contents were not significantly increased by fall fertilization, but glutamine in Chinese pine and Prince Rupprecht’s larch increased by 64.2% and 35.2%, respectively. Aboveground biomass of Prince Rupprecht’s larch had higher proline contents than Chinese pine, which suggests that the stress resistance of the aboveground tissue may be higher for Prince Rupprecht’s larch. The results indicate that different plant organs with various response are well adapted to nitrogen loading for nutrient storage in evergreen and deciduous conifer seedlings.

To investigate the effects of β-carboxyethyl germanium sequioxide (Ge-132) and germanium dioxide (GeO₂) on improving salt tolerance of evening primrose (Oenothera biennis L.), seed germination, seedling growth, antioxidase and malondialdehyde (MDA) were observed under treatments of various concentrations (0, 5, 10, 20, 30 μM) of Ge in normal condition and in 50 mM NaCl solution. The results showed that both Ge-132 and GeO₂ treatments significantly increased seed germination percentage and shoot length in dose-dependent concentrations but inhibited early root elongation growth. 5–30 μM Ge-132 and 10, 20 μM GeO₂ treatments could significantly mitigate even eliminate harmful influence of salt, representing increased percentage of seed germination, root length, ratio between length of root and shoot, and decreased shoot length. These treatments also significantly decreased peroxidase (POD) and catalase (CAT) activities and MDA content. The mechanism is likely that Ge scavenges reactive oxygen species – especially hydrogen peroxide (H₂O₂) – by its electron configuration 4S²4P² so as to reduce lipid peroxidation. This is the first report about the comparison of bioactivity effect of Ge-132 and GeO₂ on seed germination and seedling growth under salt stress. We conclude that Ge-132 is better than GeO₂ on promoting salt tolerance of seed and seedling.