Free school meals and cognitive ability: Evidence from China's student nutrition improvement plan.

The China Student Nutrition Improvement Plan (SNIP) covers 40.6 million students in the compulsory education stage, accounting for 42% of all students enrolled in rural compulsory education in 2021. This paper utilizes the county-by-county rollout of the SNIP and estimates the effect of this nutritional intervention on students' cognitive outcomes. We find that SNIP increases math test scores but has a statistically insignificant effect on verbal achievement. The effect is greater for middle school students and children from disadvantaged families. The SNIP affects the cognitive performance of students by improving their health status, increasing school attendance, fostering good study habits, raising educational expectations, and improving the human capital of peers.

Individual and combined effects of arbuscular mycorrhizal fungi and phytohormones on the growth and physiobiochemical characteristics of tea cutting seedlings.

Both arbuscular mycorrhizal fungi (AMF) and phytohormones collectively regulate plant growth and root development, but their individual and combined effects on tea [Camellia sinensis (L.) O. Kuntze] cutting seedings remain unclear. This study examined the individual and combined effects of two species of AMF (Rhizophagus intraradices, RI and Funneliformis mosseae, FM) and two types of palnt hormones (strigolactones, SLs; polyamines, PAs) on tea cutting seedings, by evaluating the growth and physiobiochemical characteristics of plants treated with the AMFs and/or hormones. The results showed that inoculation with either AMF individually or hormones treatment alone could significantly enhanced mycorrhizal colonization, growth target and physiobiochemical characteristics of tea cutting seedlings. Interestingly, the addition of a combination of AMFs and hormones showed superior effects, while SL and RI exhibited the most improvements to the colonization rate, plant growth, root-morphological traits, root DHA activity, photosynthesis, chlorophyll content, soluble sugar content in leaves, and the activities of antioxidant enzymes (SOD, POD, and CAT), compared to other treatment combinations (SL + FM, PA + RI, and PA + FM). Correlation analyses revealed a significantly (p < 0.05) positive correlation of root AMF colonization with root-related traits (e.g., DHA, root total length, surface area, and volume) and leaf-related traits (e.g., leaf area, shoot biomass, total chlorophyll, and antioxidant enzyme activities). This study demonstrated that while the apllication of individual AMF or plant hormones had a certain good effects on most growth and physiobiochemical characteristics parameters of tea cutting seedings, the additive effect was from specific combined of AMF and plant hormones. These results highlight the possibility for combined of AMF and plant hormones to improve the asexual reproduction of tea plants via cuttings.