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Waterlogging occurs due to poor soil drainage or excessive rainfall. It is a serious abiotic stress factor that negatively affects crop growth. Waterlogging often causes plants to shed leaves, fruits, and, ultimately, to die. Peach (Prunus persica) trees are generally intolerant to waterlogging, and the primary peach rootstock used in Chinais "Maotao," which has very poor resistance to sensitivity. Therefore, waterlogging has become a restriction on the development of the peach industry in many regions. In this experiment, we tested the waterlogging resistance of "Maotao (Prunus persica (L.) Batsch)" (MT), "Shannong1 (GF677 × Cadaman)" (SN1), and "Mirabolano 29C (Prunus cerasifera)" (M29C) rootstocks. Using a simulated waterlogging method, the effects of waterlogging on the photosynthetic system, leaf pigments, osmotic adjustment, lipid membrane peroxidation, and antioxidant system of these three peach rootstocks were studied, and the changes of chlorophyll fluorescence parameters and fluorescence imaging were observed. The results showed that, with prolonged waterlogging, the photosynthetic pigment content and photosynthesis of the three peach rootstocks decreased rapidly, but the decomposition rate of SN1 and M29C chlorophyll was slower, and it still had high light energy absorption and energy transfer capabilities under waterlogging stress, which reduced the damage caused by waterlogging stress; under the stress of flooding, the osmoregulatory substances of the three rootstocks increased to varying degrees compared with normal conditions. At the same time, the enzyme activity of superoxide dismutase (SOD) activity, peroxidase (POD) activity, and catalase (CAT) activity in the leaves of the three rootstocks under flooding stress all increased and then decreased; during this period, malondialdehyde (MDA) continued to increase, and SN1 and M29C were significantly lower than MT; and chlorophyll fluorescence parameters, including the maximum photochemical efficiency (Fv/Fm), actual photochemical efficiency (ΦPSII), photochemical quenching coefficient (qP), non-photochemical quenching (NPQ), and electron transfer rate (ETR) decreased significantly. The tolerance of SN1 and M29C to waterlogging was significantly better than that of MT rootstocks. The rootstock and grafted seedlings of SN1 have good waterlogging tolerance. [ABSTRACT FROM AUTHOR]

Sucrose nonfermentation 1 (SNF1) related kinase 1 (SnRK1) is a central energy sensor kinase in plants and a key switch regulating carbon and nitrogen metabolism. Fruit quality depends on leaf photosynthetic efficiency and carbohydrate accumulation, but the role of peach (Prunus persica) SnRK1 α subunit (PpSnRK1α) in regulating leaf carbon metabolism and the light signal response remains unclear. We studied the carbon metabolism of tomato leaves overexpressing PpSnRK1α and the responses of PpSnRK1α‐overexpressing tomato leaves to light signals. Transcriptome, metabolome, and real‐time quantitative polymerase chain reaction analyses revealed that uridine 5′‐diphosphoglucose, glutamate, and glucose‐6‐phosphate accumulated in tomato leaves overexpressing PpSnRK1α. The expression of genes (e.g., GDH2, SuSy) encoding enzymes related to carbon metabolism (e.g., glutamate dehydrogenase (GDH2; EC: 1.4.1.3), sucrose synthase (SS; EC: 2.4.1.13)) and chlorophyllase (CLH) encoding chlorophyllase (EC: 3.1.1.14), which regulates photosynthetic pigments and photosynthesis, was significantly increased in PpSnRK1α‐overexpressing plants. PpSnRK1α overexpression inhibited the growth of hypocotyls and primary roots in response to light. The chlorophyll content of the leaves was increased, the activity of SS and ADPG pyrophosphatase (AGPase; EC: 2.7.7.27) was increased, and photosynthesis was promoted in PpSnRK1α‐overexpressing plants relative to wild‐type plants. Under light stress, the net photosynthetic rate of plants was significantly higher in plants overexpressing PpSnRK1α than in wild‐type plants. This indicates that PpSnRK1α promotes the accumulation of carbohydrates by regulating genes related to carbon metabolism, regulating genes related to chlorophyll synthesis, and then responding to light signals to increase the net photosynthetic rate of leaves. [ABSTRACT FROM AUTHOR]

• Peach had a higher utilization rate of glycine compared with urea. • Glycine:urea (7:3) treatments significantly increased the biomass of peach. • Glycine and glycine:urea (7:3) treatments led to higher rubisco activity in leaves. • High-dose of glycine promoted the accumulation of sucrose in leaves and fruits. The unreasonable use of urea and its low nitrogen use efficiency limit peach fruit yield and quality. In this study, six different fertilization treatments—no nitrogen fertilizer, urea (T1), glycine (T2), glycine:urea (1:1) (T3), glycine:urea (3:7) (T4), and glycine:urea (7:3) (T5)—were used to explore the effects of glycine and urea on the growth, photosynthesis, sucrose metabolism, and fruit development of peach. Peach had a higher utilization rate of glycine compared with urea; combined application of glycine-urea improved the utilization rate of urea compared with T1. T5 significantly increased the biomass of peach. High-dose glycine (T2 and T5) promoted the opening of stomata and the efficiency of photosynthetic electron transfer, which increased the net photosynthetic rate (P n). In addition, the activity of Rubisco was higher in leaves on wild peach treated with T2 and T5, which increased the fixation of CO 2. Under high-dose glycine treatment, the lower cell wall invertase activity in leaves and the higher cell wall invertase activity in fruits promoted the transfer of sucrose from source to sink. In addition, high-dose glycine treatment led to higher sucrose phosphate synthase activity in leaves and fruits, which improved the accumulation of soluble sugar in the fruit. The higher sucrose transport efficiency increased the single fruit weight, soluble solid content and ratio of sugar to acid in peach fruits under high-dose glycine treatment. [ABSTRACT FROM AUTHOR]