Pear is an important fruit tree in China, and the Hexi area is the main pear-planting area in Gansu Province. Tree shapes have different effects on photosynthesis that influence fruit quality and development. Thus, in the current study, five tree shapes of Zaosu pear, including the Y-shaped, trunk, single-arm, double-arm, and spindle tree shapes, were selected, and their effects on photosynthesis and fruit quality were investigated. The thickness and length of shoot branches were highest in the single-, double-arm, and spindle tree shapes. The level of photosynthetically active radiation (PAR) varied by tree shape; from highest to lowest, the order was double-arm > single-arm > spindle > Y-shaped > trunk tree shapes. Leaf area and chlorophyll content were highest in the single- and double-arm tree shapes, with higher increases in the net photosynthetic rate to light intensity (Pn-PAR), the net photosynthetic rate to CO₂ (Pn-CO₂), the relative variable fluorescence (Vj), PSII maximum photochemical efficiency (Fv/Fm), and the light energy absorbed per unit reaction centre (ABS/RC). For fruit quality, the fruit shape index, fruit colour parameters, and content of soluble solids increased significantly in the single- and double-arm tree shapes, while the content of total acids, malic acid, and citric acid in the single- and double-arm tree shapes was lower than in the other tree shapes. All these results demonstrated that the single- and double-arm tree shapes are well ventilated and light-transmitting, which can promote fruit growth and quality.

Irrigation systems increase fruit yield of water shortage orchards in semiarid and arid lands, but their environmental impacts remain unclear. This study carries out a comparative cradle-to-gate life cycle assessment (LCA) of the furrow and drip irrigated pear production systems in the Loess Plateau of China based on 2009–2018 inventory data from integrated experimental stations. The water depletion (WD), water footprint (WF), global warming (GWP), acidification (AP), and eutrophication (EP) potentials of the furrow and drip irrigated pear production systems were calculated and compared, including the orchard installation phase (phase I), primary growing phase (phase II), low production phase (phase III), and full production phase (phase IV). Results indicated that the cumulative WD, GWP, AP, and EP of the drip irrigated system were 148.3 m³, 130.1 kg CO₂-eq, 0.9 kg SO₂-eq, and 0.6 kg PO₄-eq per ton of pear fruit harvest, respectively, which were 37.3–73.5% lower than those of the furrow irrigated system. The GWP, AP, EP, and WD of phase I to III contributed 39.3–46.1% in the drip irrigated system vs. 27.8–38.6% in the furrow irrigated system of the total amount, which should not be neglected in perennial orchard systems. The annual WFs were 0.9, 0.2, and 0.2 m³ kg⁻¹ year⁻¹ in phases II, III, and IV of the drip system, respectively, which were 50–71.4% lower than that of the furrow system. Green WF of furrow and drip irrigated systems were approximately the same, but the blue WF and grey WF of drip irrigation systems were 35.7–62.1% and 66.0–73.2% lower than those of the furrow irrigated system. The drip irrigated pear production system significantly mitigated environmental impacts and WFs, mainly due to reduced fertilizer application, water consumption, electricity, and diesel demand. Irrigation that changed from a furrow to a drip system was responsible for most environmental reductions, but 8% decreases of yields in phase IV. The outcomes from assessing the furrow and drip irrigated pear production systems could provide useful information for decision-making by the pear orchardists in the Loess Plateau.

The 14-3-3 proteins play crucial roles in regulating plant growth, development, signal transduction and abiotic stress responses. However, there exists a scarcity of research on the role of 14-3-3 proteins in responding to abiotic stress in apples. In this study, we isolated the MdGRF22 gene from the apple 14-3-3 family. Through the screening of interacting proteins and genetic transformation of Arabidopsis thaliana and apple callus tissues, the function of the MdGRF22 gene under drought stress was verified. The coding sequence (CDS) of MdGRF22 consists of 786 bp and encodes for 261 amino acids. Through sequence alignment, the conserved 14-3-3 domain was identified in MdGRF22 and its homologous genes, which also share similar gene structures and conserved motifs. Subcellular localization revealed that the MdGRF22 protein was predominantly located in the cytoplasm and cell membrane. The yeast two-hybrid (Y2H) analysis demonstrated a possible interaction between MdGRF22 and MdSK. In addition, MdGRF22 transgenic plants generally exhibited lower superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities, higher malondialdehyde (MDA) levels and relative electrolyte leakage under drought conditions compared with wild-type (WT) plants. Our study suggests that MdGRF22 may reduce the drought resistance of transgenic A. thaliana and callus tissues by interacting with MdSK. This study provides a theoretical basis for further exploring the function of 14-3-3 family genes.

Zaosu pear (Pyrus ssp. Va., Zaosu) is the main variety of pear cultivated in Gansu Province. Tree shape selection is important in pear cultivation: reasonable tree shapes affect the growth and development of fruit trees and fruit quality, which, in turn, affect the economic benefits of orchards. In this study, Zaosu pear was used as a test material, and five different tree shapes—Y, trunk, single-arm, double-arm, and spindle shapes—were studied regarding three aspects, namely, branching and leafing parameters, light radiation parameters, and root distribution, in order to provide a theoretical basis for the selection of pear tree shapes in arid areas. The results showed that the single-arm and double-arm shapes had the highest fruit weight per fruit values, reaching 280.06 g and 278.27 g, respectively, and the difference in soluble solids—12.42 mg·g⁻¹ and 12.91 mg·g⁻¹, respectively—was not significant; the mu yield of the single-arm shape was 3282 kg; and the yield of a single tree was 39.54 kg, which was the highest for the five tree shapes. The trees mainly had short fruiting branches when they entered the fruiting stage, and the double-arm shape had the highest number of short fruiting branches, which was significantly higher than those of the other tree shapes. Correlation analysis revealed that the number of long fruiting branches was significantly and positively correlated with axillary flower buds. The distribution of light intensity for all five tree shapes showed a gradual increase from bottom to top and from inside to outside, and the single-arm and double-arm shapes had a uniform distribution of light intensity, which translated into better growth and fruiting potential. The trunk shape had the largest leaf area index, resulting in too much depression within the canopy and reducing light, while the single-arm and double-arm shapes had the smallest leaf area indexes, resulting in the light being evenly distributed inside and outside the canopy, and the percentage of light intensity was greater than 50% in all cases, reaching up to 80%. The double-arm form had the highest chlorophyll a content of 24.55 mg·g⁻¹, implying the ability to convert more light energy into chemical energy, and the content of chlorophyll a + b was highest in the single-arm form and the double-arm form, with values of 31.13 mg·g⁻¹ and 33.65 mg·g⁻¹. The total length of the root system and the total surface area of the root system for the single-arm shape were the largest, i.e., 558,550.64 cm and 79,252.32 cm², respectively, indicating that it has stronger adaptability and resource acquisition ability compared to the other tree shapes. In conclusion, the single-arm form is more suitable for planting in arid areas.