Silicon distribution in meadow steppe and typical steppe of northern China and its implications for phytolith carbon sequestration

Abstract

Silicon (Si) not only plays an important role in plant growth but also contributes significantly to the long‐term terrestrial carbon sink in the form of phytoliths. This study investigated Si content of 184 plant species in meadow steppe and typical steppe of northern China to examine the influential factors of Si distribution and evaluate the potential phytolith carbon sequestration of these grasslands. Our results indicated that the average Si content generally decreased in the following order of Equisetopsida > Monocotyledoneae > Dicotyledoneae. Within angiosperms, although most Si accumulator plants were commelinid monocots, many eudicots also accumulated abundant Si in their above‐ground tissues. The Si content of plant above‐ground parts in typical steppe (6.53 ± 2.88 g/kg) was significantly higher than that in meadow steppe (2.15 ± 0.92 g/kg). The estimated phytolith‐occluded carbon (PhytOC) production flux in typical steppe (0.81 ± 0.36 kg CO2 ha−1 year−1) was higher than that in meadow steppe (0.54 ± 0.23 kg CO2 ha−1 year−1). This study demonstrates that plant phylogeny influences the Si content of individual species, whereas grassland type with different mean annual precipitation and mean annual temperature may significantly affect the abundance of high Si species. We conclude that increasing the abundance of grass species with high Si content in meadow steppe and appropriate grazing and fertilizer application in typical steppe will enhance the phytolith carbon sequestration in grasslands of northern China.

Silicon addition improves plant productivity and soil nutrient availability without changing the grass:legume ratio response to N fertilization

“…Silicon addition did not affect soil organic C (Table S1). This finding contrasts with recent reports 23,30,31 that demonstrated that Si addition significantly increased soil total organic C and phytolith C sequestration. This could be because the short or long duration of the experiment for some studies found that Si plays an important role in regulating the global C balance and C turnover 32,33 .…”

“…For example, Gao et al 42 and Song et al 43 found that there were no significant effects on soil NH 4 + -N concentrations among control and N addition plots in an alpine meadow and a Korean pine plantation. The different findings may be caused by the different environmental conditions 30,44 . The present study showed that fertilization with N + Si increased the soil NH 4 + -N and NO 3 − -N concentrations.…”

“…This was probably because Si helps to increase the erectness of leaves, which, in turn, reduced self-shading and increased the net photosynthetic rate, eventually leading to an increase in the abovegroundbiomass 6,47 . Some studies have shown that Si application increases the net photosynthesis rate and water use efficiency, while the expression of some key genes related to photosynthesis is increased with Si addition even under unstressed conditions 13,30 . Higher N fertilization rates resulted in a significant reduction in abundance and aboveground biomass of legume PFTs (Fig.…”

Phytolith‐occluded carbon sequestration potential in three major steppe types along a precipitation gradient in Northern China

“…(2016) suggested that the belowground productivity of plants could play a dominant role in PhytOC production in grassland ecosystems; and Ji et al. (2018) reported that Si distribution in the aboveground parts, thus the PhytOC sequestration potential, of grassland plants, varies markedly among plant species and across grassland types. However, the effects of grassland type and species composition on the production rate of phytoliths and PhytOC (including the above‐ and belowground parts) are still not fully understood.…”

Silicon Fertilizer Application Promotes Phytolith Accumulation in Rice Plants

“…Phytoliths derive from bio-mineralization in plants and usually take the shape of the plant cell or cell spatium where Si is deposited. The phytolith content of plants ranges from less than 50 g kg -1 to as high as 150 g kg -1 (Epstein, 1994; Parr et al, 2010; Song et al, 2013, 2017; Ji et al, 2017), mainly due to phylogenetic differences in Si requirements of most dicotyledons and some Gramineae (Hodson et al, 2005), as well as the amount of available silica in the environment (Seyfferth et al, 2013; Guo et al, 2015; Si et al, 2018; Wen et al, 2018).…”