Journal Article

Relationships Between Photosynthetic Activity and Silica Accumulation with Ages of Leaf in <i>Sasa veitchii</i> (Poaceae, Bambusoideae)

Hiroyuki Motomura, Kouki Hikosaka and Mitsuo Suzuki

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 101, issue 3, pages 463-468
Published in print February 2008 | ISSN: 0305-7364
Published online November 2007 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcm301
Relationships Between Photosynthetic Activity and Silica Accumulation with Ages of Leaf in Sasa veitchii (Poaceae, Bambusoideae)

More Like This

Show all results sharing these subjects:

  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Background and Aims

Bamboos have long-lived, evergreen leaves that continue to accumulate silica throughout their life. Silica accumulation has been suggested to suppress their photosynthetic activity. However, nitrogen content per unit leaf area (Narea), an important determinant of maximum photosynthetic capacity per unit leaf area (Pmax), decreases as leaves age and senescence. In many species, Pmax decreases in parallel with the leaf nitrogen content. It is hypothesized that if silica accumulation affects photosynthesis, then Pmax would decrease faster than Narea, leading to a decrease in photosynthetic rate per unit leaf nitrogen (photosynthetic nitrogen use efficiency, PNUE) with increasing silica content in leaves.

Methods

The hypothesis was tested in leaves of Sasa veitchii, which have a life span of 2 years and accumulate silica up to 41 % of dry mass. Seasonal changes in Pmax, stomatal conductance, Narea and silica content were measured for leaves of different ages.

Key Results

Although Pmax and PNUE were negatively related with silica content across leaves of different ages, the relationship between PNUE and silica differed depending on leaf age. In second-year leaves, PNUE was almost constant although there was a large increase in silica content, suggesting that leaf nitrogen was a primary factor determining the variation in Pmax and that silica accumulation did not affect photosynthesis. PNUE was strongly and negatively correlated with silica content in third-year leaves, suggesting that silica accumulation affected photosynthesis of older leaves.

Conclusions

Silica accumulation in long-lived leaves of bamboo did not affect photosynthesis when the silica concentration of a leaf was less than 25 % of dry mass. Silica may be actively transported to epidermal cells rather than chlorenchyma cells, avoiding inhibition of CO2 diffusion from the intercellular space to chloroplasts. However, in older leaves with a larger silica content, silica was also deposited in chlorenchyma cells, which may relate to the decrease in PNUE.

Keywords: Sasa veitchii; bamboo; leaf; silica accumulation; photosynthetic capacity; nitrogen content; photosynthetic nitrogen use efficiency; leaf age; leaf senescence

Journal Article.  3757 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.