Chinese jujube (also called Chinese date, Ziziphus jujuba Mill.) is an economically important tree in China and provides a rich source of sugars, vitamins, and bioactive components, all of which are indispensable and essential for the composition and participation in life processes of the human body. However, the location of these metabolites in jujube fruits has not been determined. This study applied matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate the spatial distribution of sugars, organic acids, and other key components in jujube fruits at different developmental periods. Soluble sugars such as hexoses and sucrose/maltose significantly increase with fruit ripening, while organic acids show an overall trend of initially increasing and then decreasing. Procyanidins and rutin exhibit specific distributions in the fruit periphery and peel. These findings suggest that MALDI-MSI can be used to study the spatial distribution of nutritional components in jujube fruits, providing insights into the changes and spatial distribution of substances during jujube fruit development. This technique offers a scientific basis for jujube breeding, utilization, and production.

Juniperus sabina L., a shrub distributed in patches in arid and semi-arid areas of the northern hemisphere, plays an important role in preventing land desertification and maintaining ecosystems. However, few studies have reported genetic diversity and genetic structure of widely distributed populations of J. sabina in northwest China. Here, we evaluated the genetic diversity and genetic structure and predicted the isolation barriers among 11 populations based on 20 simple sequence repeats (SSRs). A total of 134 alleles were generated and the average number of alleles per locus was 6.70. The Shannon diversity index ranged from 0.659 to 0.951, with an average of 0.825. Population structure analysis revealed that the populations were assigned into two genetic groups. The analysis of molecular variance (AMOVA) indicated that 88% of genetic variation existed within populations. Moderate population differentiation was occurred with F_ST value of 0.090. Finally, we concluded that geographic isolation is the main factor affecting the genetic structure of J. sabina populations. The results of this study provide a foundation for the strategies for J. sabina genetic conservation and management.

Salix psammophila C. Wang & Chang Y. Yang is a desert plant species distributed in Northwest China. Here, we report the complete choroplast genome sequences in order to enrich its genetic resource. The total genome is 155,278 bp in length and contains a typical quadripartite structure, including a large single copy (LSC) region of 84,457 bp, a small single copy (SSC) region of 15,891 bp, and a pair of inverted repeats (IRs) of 27,465 bp. There were 130 genes in the genome, including 85 protein-coding genes, 37 tRNA genes and eight rRNA genes. The overall CG content in the plastome of S. psammophila is 36.72%. The phylogenetic tree based on 18 complete plastomes of Salicaceae support close relationships among S. psammophila, Salix taoensis, and Salix rehderiana.

A field experiment was conducted in 2023 and 2024 in Beijing, China, to investigate effects of soil water stress, applied before the fruit ripening stage, on the fruit total soluble solid accumulation and cracking of jujube trees. The experiment consisted of two variation factors: (a) irrigation levels (MDI and SDI, applied 80% and 50% of the irrigation volume, respectively) and (b) growth stages (stage 1, before the fruit enlargement stage, and 2, before the fruit ripening stage). The two irrigation levels were applied at each growth stage in a 2 × 2 factorial arrangement, plus a control treatment receiving 100% irrigation volume, resulting in five treatments per replicate. The findings indicated that pre-enlargement stage water stress enhanced the accumulation of total soluble solid content within fruits, which subsequently promoted faster fruit growth in from the early- to mid-August period. However, by late August, both the total soluble solid content and fruit growth rates had declined, thereby mitigating the risk of fruit cracking. During the fruit enlargement stage, the fruit total soluble solid content in SDI-2 increased by approximately 24% by the end of August compared to the control, leading to lower osmotic potential and higher turgor pressure during the following ripening stage. As skin growth ceased, high turgor pressure caused fruit cracking at the following ripening stage. The SDI-2 treatment demonstrated a fruit cracking rate approximately 1.5 times higher than that of the control. Pearson correlation analysis also indicated that fruit cracking was positively correlated with total soluble solids accumulated in August. Meanwhile, the yield of SDI-2 was reduced about 18%. Therefore, the adequate soil moisture during the fruit enlargement stage was crucial to minimize jujube fruit cracking and economic losses. Meanwhile, the deficit irrigation applied during the pre-enlargement stage could effectively conserve water resources and mitigate the occurrence of extensive jujube fruit cracking.

Ziziphus jujuba Mill. is an important economic tree species in China with nutritional, ecological and ornamental values, and its fruits show abundant variations in size and shape. Phytohormones regulate fruit morphogenesis, yet the spatial distribution characteristics of endogenous phytohormones in jujube fruits with different shapes remain unclear. In this study, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was applied to explore the spatial distribution patterns of phytohormones in round, constricted and long jujube fruits. The results indicated that phytohormones were uniformly distributed in the flesh and pericarp of round and constricted fruits. Certain auxins and gibberellins were undetectable in the outer pericarp of long fruits, while one cytokinin was predominantly accumulated at the fruit base. The differential distribution of phytohormones is likely a potential factor triggering jujube fruit morphological differentiation. This study clarifies the spatial variation in endogenous phytohormones, helping elucidate the regulatory mechanism of jujube fruit shape.

Soil water flux is a key parameter for understanding water and heat transport processes in the vadose zone. The heat pulse technique (HPT) has shown considerable potential for predicting soil water flux. Traditional three-needle probe methods, the maximum dimensionless temperature difference (MDTD) method and the ratio of downstream to upstream temperature increases (Ratio) method, can only measure water flux along the probe alignment. To enhance the applicability of the HPT method, the five-needle probe with vector addition allows for the measurement of soil water flux in any direction within the plane perpendicular to the needles. However, its applicability across different soil textures remains unclear. The objective of this study was to evaluate the applicability of the MDTD and Ratio methods when combined with vector addition across different soil textures. Experimental results show that the vector MDTD and Ratio methods improve water flux measurement accuracy compared with traditional three-needle methods, confirming the reliability of the vector HPT approach. Specifically, the mean absolute percentage error (MAPE) of the vector MDTD method decreased by 1.69%, 1.04%, and 1.80% in sand, sandy loam, and silt loam, respectively, compared with the traditional MDTD method. In contrast, the MAPE of the vector Ratio method varied by +8.83%, −6.73%, and −18.20% in the same soils, relative to the traditional Ratio method. Examining the root mean square error (RMSE) of each method yields a similar conclusion. Similarly to traditional HPT methods, the measurement accuracy of the vector HPT approach is influenced by soil texture, water flux range, and probe spacing. Notably, because the vector HPT method involves four probe spacings, namely the distances between the heating needle and the temperature-sensing needles, it can exacerbate the instability of the resultant water flux measurements. These findings may facilitate the broader application of the HPT method.