Spatiotemporal patterns of leaf nutrients of wild apples in a wild fruit forest plot in the Ili Valley, China.

Malus sieversii, commonly known as wild apples, represents a Tertiary relict plant species and serves as the progenitor of globally cultivated apple varieties. Unfortunately, wild apple populations are facing significant degradation in localized areas due to a myriad of factors. To gain a comprehensive understanding of the nutrient status and spatiotemporal variations of M. sieversii, green leaves were collected in May and July, and the fallen leaves were collected in October. The concentrations of leaf nitrogen (N), phosphorus (P), and potassium (K) were measured, and the stoichiometric ratios as well as nutrient resorption efficiencies were calculated. The study also explored the relative contributions of soil, topographic, and biotic factors to the variation in nutrient traits. The results indicate that as the growing period progressed, the concentrations of N and P in the leaves significantly decreased (P < 0.05), and the concentration of K in October was significantly lower than in May and July. Throughout plant growth, leaf N-P and N-K exhibited hyperallometric relationships, while P-K showed an isometric relationship. Resorption efficiency followed the order of N < P < K (P < 0.05), with all three ratios being less than 1; this indicates that the order of nutrient limitation is K > P > N. The resorption efficiencies were mainly regulated by nutrient concentrations in fallen leaves. A robust spatial dependence was observed in leaf nutrient concentrations during all periods (70.1-97.9% for structural variation), highlighting that structural variation, rather than random factors, dominated the spatial variation. Nutrient resorption efficiencies (NRE, PRE, and KRE) displayed moderate structural variation (30.2-66.8%). The spatial patterns of nutrient traits varied across growth periods, indicating they are influenced by multifactorial elements (in which, soil property showed the highest influence). In conclusion, wild apples manifested differentiated spatiotemporal variability and influencing factors across various leaf nutrient traits. These results provide crucial insights into the spatiotemporal patterns and influencing factors of leaf nutrient traits of M. sieversii at the permanent plot scale for the first time. This work is of great significance for the ecosystem restoration and sustainable management of degrading wild fruit forests.

Associations between uterine fibroids and obstetric outcomes in twin pregnancies.

OBJECTIVE: To examine potential associations between the presence of fibroids and obstetric outcomes in twin pregnancies. METHODS: A prospective cohort study compared obstetric outcomes between individuals with twin pregnancies who did and did not have fibroids. Patients were considered for inclusion if they underwent first-trimester ultrasonography examination, and went on to deliver at the Beijing Obstetrics and Gynecology Hospital between September 1, 2012 and December 31, 2014. Participants were grouped based on the presence or absence of fibroids and baseline demographics, fibroid characteristics, and obstetric outcomes were recorded and compared between the two groups. RESULTS: In total, 153 patients with twin pregnancies were recruited; 51 had fibroids and 102 did not. Patients in the fibroid group demonstrated a higher maternal age (P<0.001), higher pre-pregnancy body mass index (P=0.01), and higher rate of assisted reproductive technology use (P=0.04). The presence of fibroids was not associated with any change in obstetric outcomes, and obstetric outcomes were unaffected by the number, size, location, and type of fibroids (all P>0.05). CONCLUSION: Fibroids were not a risk factor for any adverse obstetric outcomes among patients with twin pregnancies.