Effects of fertilization and drought stress on tannin biosynthesis of Casuarina equisetifolia seedlings branchlets

Abstract

Nutrient, water, and their interactions influence the allocation of investment by plants to resistance and tolerance traits. We used a completely crossed randomizedblock design experiment to examine the independent and interactive effects of nutrients and water availability on tannin production of C. equisetifolia seedlings. The results showed that nitrogen and phosphorus fertilizer have significant effects on total phenolics (TP) and extractable condensed tannins (ECT) concentrations of branchlets. TP and ECT concentrations decreased with fertilizer addition and increased in arid condition. This pattern lends to support source-sink hypothesis such as the carbon-nutrient balance (CNB) hypothesis and the growth-differentiation balance (GDB) hypothesis. Soluble sugars or starch concentrations were both inversely related to TP concentrations. However, there was no significant correlation between them and ECT concentrations. In addition, chlorophyll concentration had a positive linear correlation with TP and no significant correlation with ECT. On the contrary, chlorophyll a/b ratios were negatively correlated with TP and positively correlated with ECT. The discrepancy of relationship between carbohydrates and TP or ECT showed that the biosynthetic routes of different tannins were different. In this study, no significant correlation between TP and N, or ECT and N, did not support protein competition model (PCM). TP:N and ECT:N ratios were higher in nutrient deficiency and arid conditions, which were one of the important nutrient conservation strategies for C. equisetifolia.

Seasonal Variation of Tannin and Nutrient in Aegiceras corniculatum Leaves in Zhangjiang Mangrove Ecosystem

“…Generally, the contents of tannins and nutrient in plant tissue had opposite trend, thus the TP: N and ECT: N ratio could be used to indicate the health quality of the leaves [36]. In this study, TP: N and ECT: N in the sun leaves were significantly higher than that in shade leaves except for autumn (Fig.…”

Effects of elevation and nitrogen and phosphorus fertilization on plant defence compounds in subarctic tundra heath vegetation

“…These findings are consistent with studies showing that increased foliar P can coincide with a reduction in polyphenols (Zhang et al . ), because of reduced plant nutrient limitation leading to greater carbon allocation to primary growth as opposed to secondary metabolite production (Bryant, Chapin & Klein ). In this system, N and P have been shown to co‐limit plant biomass (Sundqvist et al .…”

“…This analysis is justified on the basis that increasing foliar nutrient concentrations are usually associated with declines in secondary metabolites (Zhang et al . ).…”

“…), others have found polyphenol concentrations in plants to increase (Feller ), or decrease (Zhang et al . ) with increasing P availability. Further, structural defences such as lignin have been shown to decrease with increasing N (Haukioja et al .…”

“…In contrast, it has been proposed that phosphorus (P) availability is unimportant in polyphenol production, because it does not directly affect the phenylalanine pathway responsible for synthesizing proteins and many polyphenols (Jones & Hartley 1999). However, while some results provide evidence for this (Koricheva et al 1998), others have found polyphenol concentrations in plants to increase (Feller 1995), or decrease (Zhang et al 2012) with increasing P availability. Further, structural defences such as lignin have been shown to decrease with increasing N ) and P (Santiago, Schuur & Silvera 2005) availability.…”