Increased CO2 and nutrient status changes affect phytomass and the production of plant defensive secondary chemicals in Salix myrsinifolia (Salisb.)

Abstract

The effect of CO enrichment (700 and 1050 ppm) on phytomass, soluble sugars, leaf nitrogen and secondary chemicals of three Salix myrsinifolia clones was studied in plants cultivated at very poor (sand seedlings) and moderate (peat seedlings) nutrient availability and under low illumination. The total shoot phytomass production of sand scedlings was less than 10% of that of the peat seedlings. Carbon dioxide increased the total shoot phytomass of peat seedlings. When the ambient carbon supply was doubled (to 700 ppm) the growth of sand seedlings was slightly enhanced but 1050 ppm CO gave growth figures similar to those at the control CO level. Leaf nitrogen content and total soluble sugar contents were significantly higher in peat seedlings than in sand seedlings. Leaf nitrogen showed a decreasing trend in relation to CO increase. On the other hand, CO did not have any clear-cut effect on total sugars. At the control CO level the content of salicortin, which is a dynamic phenolic, was higher in the peat seedlings than in the sand seedlings, but salicin showed the opposite trend. CO enrichment considerably decreased these phenolics in the peat seedlings. At the control CO level, the content of more static phenolics, such as proanthocyanidins, was higher in sand seedlings. An increased carbon supply considerably increased static phenolics in the peat seedlings. Willow defence against generalist herbivores is moderately decreased by enhancement of atmospheric carbon dioxide.

The effect of elevated atmospheric CO2 concentration and nutrient supply on gas exchange, carbohydrates and foliar phenolic concentration in live oak (Quercus virginiana Mill.) seedlings

“…virginiana seedlings were using photosynthates mainly for growth [52] and thus non-structural carbohydrates (sugars and starch) did not accumulate in any plant compartment. Soluble sugars and starch concentrations in stem and roots have already been found not to increase in other experiments [4,28]. In contrast with our findings, starch and total non-structural carbohydrate accumulation in foliage (and other compartments) of plants grown at elevated [CO 2 ] is a much more common phenomenon [2,42,43], although it has been reported to be a strong species-specific response [29,50].…”

“…In contrast with our findings, starch and total non-structural carbohydrate accumulation in foliage (and other compartments) of plants grown at elevated [CO 2 ] is a much more common phenomenon [2,42,43], although it has been reported to be a strong species-specific response [29,50]. We sampled the plant material in the afternoon and Wullschleger et al [56] [28,31,41]. In our experiment the CO 2 effect on increasing phenolic concentration took place without a parallel increase in total non-structural carbohydrates at elevated [CO,] that otherwise would have presumably diluted phenolics.…”

“…The increased foliar phenolic concentration in conjunction with increased C/N ratios may alter the performance of herbivores of Q. virginiana in the regeneration phase, in view of projected increases in atmospheric [ CO 2 ]. Foliar phenolics decreased following leaf maturation [28]. Nutrient treatment did not affect phenolic concentration.…”

Effects of elevated carbon dioxide on leaf gas exchange and growth of cork-oak (Quercus suber L) seedlings

“…CO 2 has been reported to be able to change both plant physiology and growth (Field et al, 1992;Mousseau and Saugier, 1992 (Bowes, 1993;Guehl et al, 1994;Idso and Idso, 1994 (Evans, 1989), this decrease could lead to a limitation of photosynthesis capacity under elevated CO 2 . Such a decrease has been observed in a range of tree species (Johnsen, 1993;Julkunen-Tiitto et al, 1993;Lindroth et al, 1993;Duff et al, 1994). By comparing oaks growing naturally in elevated CO 2 with those growing in ambient CO 2 , Körner and Miglietta (1994) Ceulemans and Mousseau (1994).…”

The effect of u.v.‐B radiation on u.v.‐absorbing secondary metabolites in birch seedlings grown under simulated forest soil conditions

“…It has been observed that, although their growth is restricted, some trees are able to maintain a moderate concentration of secondary metabolites, despite low nutrient availability (see, for example, Julkunen-Tiitto, Tahvanainen & Silvola, 1993;Hakulinen, Julkunen-Tiitto & Tahvanainen, 1995). In Finland, birch trees often grow in habitats where their growth rate is depressed by a shortage of nutrients; simulated forest-soil conditions used in this study correspond to the natural growth habitats of birch trees.…”