Interactions between soil water and fertilizer on leaf photosynthesis and δ13C of Catalpa bungei seedlings

Abstract

Abstract:Our objective was to identify combinations of irrigation and fertiliser application that promoted the photosynthetic productivity and water use efficiency (WUE) of Catalpa bungei. Using response surface methodology based on a rotatable central composite design, we conducted a pot experiment with C. bungei clone 004-1 seedlings. The experiment quantified the effects of interactions between soil water content (W), nitrogen application rate (N), and phosphorus application rate (P) on leaf net photosynthetic rates (Pn), SPAD values (SPAD-502 meter readings of leaf chlorophyll), and carbon isotope composition (δ 13 C). N had significantly positive effects on the all three leaf parameters, while W had significantly negative effects on leaf δ 13 C signatures but positive effects on leaf Pn and SPAD values. The magnitude of the N effect exceeded that of the W effect. P had no significant effects on any of the three leaf parameters. The W × N interaction had significant positive effects on Pn and SPAD, but significant negative effects on leaf δ 13 C. Thus, irrigation and nitrogen application had different effects on seedling growth and WUE, and the two effects were interactive. Catalpa bungei growth was promoted by appropriately increasing nitrogen application and irrigation, but WUE was improved by increasing N and decreasing irrigation. Therefore, strategies for the irrigation and fertilisation of C. bungei plantations should be designed to appropriately balance plant growth and WUE.

Dry Season Irrigation Promotes Leaf Growth in Eucalyptus urophylla × E. grandis under Fertilization

“…In the equation, t 1 , t 2 , and t 3 represent the initial process (the beginning of the rapid growth of the leaves), the peak period (the peak period of leaf growth), and the end stage (the end period of the rapid growth of the leaves), respectively [24]. The leaf expansion rate (cm −2 •day −1 ) was for a single leaf area/peak period [25]. The leaf expansion rate in this paper was the relative leaf expansion rate in the peak period.…”

Biological control of Fusarium crown rot of wheat with Chaetomium globosum 12XP1-2-3 and its effects on rhizosphere microorganisms

“…C. globosum can improve the defense enzyme activity of plants under adversity stress and stimulate the expression of resistance-associated genes, thus inducing plant systemic resistance ( Yin, 2014 ; Cong et al, 2015 ; Zhang et al, 2016 ). Moreover, it has been reported that the application of C. globosum agents can significantly increase the content of organic matter, nitrate nitrogen, and ammonia nitrogen, and the activity of soil urease, sucrase, and alkaline phosphatase, as well as affect the distribution of bacterial communities in the soil, and increase the number and diversity of bacteria, thus promoting the growth of Catalpa bungei and Malus hupehensis seedlings ( Song et al, 2015 ; Li, 2019 ). Therefore, C. globosum exhibits great biocontrol potential in disease prevention and growth promotion of plants.…”