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Titanium has been reported to have positive effects on crop growth and production in various species. However, the impact of titanium on the Tartary buckwheat crops has not yet been studied. Therefore, an experiment was conducted to investigate the effect of spraying different concentrations of ionic titanium on the growth, photosynthesis, and uptake of mineral nutrients in Tartary buckwheat. The results showed that the application of titanium significantly improved dry matter accumulation, internode diameter, main stem node, root length, root average diameter, root surface area, root volume, grains per plant, and weight of grains per plant. Additionally, chlorophyll and photosynthetic parameters showed improvement regardless of the concentration of titanium used. The study found that titanium accumulation was mainly in leaves. The content of titanium in leaves showed a significant positive correlation with K, Ca, Mg, Mn, Cu, Zn, and B. This suggests a potential synergistic relationship between titanium and minerals in Tartary buckwheat leaves. Furthermore, the study also observed a significant increase in the total accumulation of P, K, Ca, Mg, Mn, Cu, Zn, and B in Tartary buckwheat plants. Overall, this study provides evidence for the positive effects of titanium on Tartary buckwheat and offers a theoretical foundation for practical production.

Tartary buckwheat is a cereal crop that has both medicinal and food origins. However, the underlying factors that contribute to Tartary buckwheat’s flowering and seed-setting characteristics, effective grain formation, and physiological changes are still not well understood. This study aimed to investigate the flowering and seed-setting characteristics of different parts of Tartary buckwheat, as well as the grain-filling characteristics after flowering. To achieve this, Tartary buckwheat cultivars with high (QK3) and low (XQ2) seed-setting rates were selected for pot and field experiments. The study found that Tartary buckwheat undergoes flowering and seed setting simultaneously. Many wilted flowers and grains were observed 45 and 51 d after flowering. Compared to XQ2, QK3 exhibited a higher grain formation rate and seed-setting rate by 7.42% and 26.16%, respectively. Additionally, QK3 had a significantly lower grain abortion rate by 12.03%. The 1000-grain weight and average grain-filling rate of QK3 were 11.10% and 14.81% higher than those of XQ2, respectively. QK3 exhibited a faster maximum grain-filling rate (Rmax), reaching 18.38% faster than XQ2. Additionally, the dry matter average distribution rate in the main stem and branched grains of QK3 was 13.26% and 23.07% higher than that of XQ2, respectively. The sucrose concentration, SS, and SSS enzyme activities of QK3 were all higher than those of XQ2, by 0.29–25.99%, 5.22–11.62%, and 6.64–12.47%, respectively. Correlation analysis revealed a significant positive correlation between sucrose, soluble sugar, and starch concentration during the grain formation process and SS and SSS activities. This suggests that the levels of SS, SSS, soluble sugar, and sucrose in the grain play a crucial role in grain filling.

Oats (Avena sativa L.) are mostly used as a germplasm resource for forage. This experiment showed the differences in the nutrient composition and the forage quality of five wild leather oat populations from Israel and one cultivated leather oat population from China. It also showed the correlation of the indicators with the geo-environmental factors in the places of origin of the six populations that were analysed. Three replicated experiments were conducted during a three-year period from 2018.10 to 2020.03, mainly from 11 indicators of nutrient composition and forage quality. In this experiment, Spearman’s correlation was used to analyse the differences between different groups (p < 0.05), the relationship between components was analysed by principal component analysis (PCA), and the kinship relationship between six groups was also analysed based on the data of 11 components. In terms of nutrient content, the cultivated group Hu had significantly lower ash (8.92%), crude protein (11.96%), and soluble sugar content (10.51%) than the wild oat groups. In terms of forage quality, the lignin content (3.31%) of the Hu population was 2.3 times higher than that of Evolution Canyon, and the fibre content was 8 times higher than that of Sede Boqer. This indicates that wild oats have better nutritional value and palatability. Following the correlation analysis, it was found that the environmental factors of the origin had a significant effect on the indexes of ash, crude protein, and soluble sugar of oat straw, but had less effect on the content of crude fat, total phosphorus, and total potassium. Meanwhile, the annual rainfall and the number of rainfall days in the origin had a significant effect on the fibre content. In conclusion, the higher variability of wild oat populations due to the influence of different environmental and geographical factors may be a new possibility brought by forage oats.

Exogenous melatonin (MT) regulates plant growth and mitigates stress in response to stress. To analyze the machinery of exogenous melatonin, which improves salt and alkaline tolerance in oats, MT’s function was identified in the oat seed germination stage in our previous study. In this study, morphogenesis, photosynthetic physiology, hormone levels, and ion homeostasis were evaluated using the same MT treatment concentration. The results revealed that compared to the S45 treatment, the 100 μmol·L−1 MT treatment efficiently increased the seedling height and main root length of oat seedlings; promoted secondary root development; enhanced the root volume and root surface area; maintained a higher photosynthetic pigment content (carotenoids; chlorophyll a; chlorophyll b); raised the leaf photosynthetic rate (Pn), intercellular CO2 concentration (Ci), conductance to H2O (Gs), and transpiration rate (Tr); enhanced the light energy absorption and conversion of leaves; increased the leaf GA3, Tryptamine (TAM), and IAA contents; and decreased ABA levels. Hierarchical cluster analysis revealed that MT treatment also increased the contents of P, K, Ca, Mn, Cu, Mg, Fe, Zn, Mo, Cd, Al, Se, Ni, Co, and Ti; decreased the Na/K ratio; and maintained cellular ionic homeostasis in oat seedlings under saline–alkali stress, as compared with the untreated group. These findings showed that MT treatment enhanced the adaptation of oat to saline–alkali stress through regulating the physiological process of seedling growth. This suggests that MT plays a different role in improving saline–alkali tolerance in the germination and seedling stages of oat.

Saline–alkali stress is one of the major factors limiting oat seed germination. The regulatory role of melatonin (MT) as a naturally occurring active substance is well known, but the mechanism of MT-mediated intrinsic physiological regulation of oat seed germination under saline–alkali stress is unclear. Therefore, this study investigated (1) the variability of different MT seed soaking concentrations and times on the germination of oat seeds under saline–alkali stress, and (2) the possible physiological regulatory mechanisms of MT on the germination of oat seeds under saline–alkali stress. The results showed that seed vigor was significantly reduced under saline–alkali stress, and seed germination of oats was significantly inhibited; different concentrations of MT seed soaking treatments improved the germination rate, germination potential, germination index, vigor index, root length, germ length, fresh weight, and dry weight; and, overall, treatment improved seed germination and exhibited the phenomenon of “low promotion and high inhibition”. The 100 μmol·L−1 MT seed soaking treatment effectively enhanced the activities of seed antioxidant enzymes (SOD, POD, CAT, and APX) and nonenzymatic antioxidants (GSH and AsA), affected the AsA-GSH cycle, and effectively increased the contents of osmoregulatory substances (proline, protein, and soluble sugar) by reducing levels of H2O2, OH−, and MDA, thus enhancing the tolerance of oats to saline–alkali and promoting seed germination. In conclusion, MT has a positive effect on the saline–alkali tolerance of oat seeds.

Photosynthesis is the basis for plant productivity, and improvement of photosynthetic efficiency is an important way to improve crop yield. However, the relationship between photosynthetic parameters and the yield of Tartary buckwheat (Fagopyrum tataricum) under rainfed conditions is unclear. A two-year field trial was conducted during 2016 and 2017 to assess the photosynthetic capacity of different leaves, dry matter accumulation, and yield of four Tartary buckwheat cultivars from flowering to maturity. The leaves of all cultivars aged gradually after flowering, and the leaf chlorophyll (Chl) and soluble protein (SP) contents, net photosynthetic rates (Pn), transpiration rates (Tr), and stomatal conductance (Gs) tended to decline. The Chl, SP, Pn, Tr, and Gs of cultivars (cvs.) XiQiao2 and QianKu3 were significantly higher than those of LiuKu3 and JiuJiang at each sampling time from 18 days after anthesis to maturity, but the intercellular CO2 content (Ci) showed the opposite trend. Cultivars XiQiao2 and QianKu3 produced more total dry matter (mean 17.1% higher), had higher harvest index (HI, mean 16.4% higher), and yield (mean 29.0% higher) than cvs. LiuKu3 and JiuJiang at maturity, and the difference was remarkably consistent. The yield of all the cultivars was positively correlated with leaf Chl, SP, Pn, Tr, and Gs, but negatively correlated with Ci. At late growth stages, the high-yielding cultivars maintained higher Chl, SP contents, Pn, Tr, and Gs, and showed higher dry matter accumulation and lower Ci than the low-yielding cultivars, consistent with their higher leaf photosynthetic capacity. The important factors determining the yield of Tartary buckwheat were maintaining higher leaf Chl and SP content and photosynthetic capacity and delaying aging during the grain formation stage. Enhanced rates of photosynthesis and dry matter accumulation led to higher post-anthesis accumulation of biomass with a positive impact on grain number and higher yield.