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Autumnal leaf senescence in Miscanthus × giganteus and leaf [N] differ by stand age.

Boersma NN, Dohleman FG, Miguez FE, Heaton EA - J. Exp. Bot. (2015)

Bottom Line: By the end of the growing season, first-year M. × giganteus had A and ΦPSII rates up to 4 times greater than third-year M. × giganteus, while leaf [N] was up to 2.4 times greater.The increased photosynthetic capability and leaf N status in first-year M. × giganteus suggests that the photosynthetic apparatus was not dismantled before a killing frost, thus potentially limiting nutrient translocation, and may explain why young M. × giganteus stands do not survive winter when older stands do.Because previous senescence research has primarily focused on annual or woody species, our results suggest that M. × giganteus may be an interesting herbaceous perennial system to investigate the interactive effects of plant ageing and nutrient status on senescence and may highlight management strategies that could potentially increase winter survival rates in first-year stands.

View Article: PubMed Central - PubMed

Affiliation: Department of Agronomy, Iowa State University, Ames, IA 50011, USA.

No MeSH data available.


Related in: MedlinePlus

Miscanthus × giganteus senescence response to date and average daily temperature. Net CO2 assimilation rate (A, μmol m–2 s–1) (A, B), photosystem II efficiency (ΦPSII, dimensionless) (C, D), and total leaf N ([N], %) (E, F) were measured in autumn 2010 (A, C, E) and 2011 (B, D, F). Measurements were made on two randomly chosen plants per plot and were averaged within eight plots for first-year (closed circles), second-year (closed squares) and third-year (closed triangles) M. × giganteus on each date. Points plotted indicate the mean of these eight (n=8) observations within each stand age and date combination. Error bars indicate ±1 standard error of the mean. Average daily temperatures (solid line) and daily low temperatures (dotted line) were recorded at an adjacent (6.3 km NE) weather station and acquired from the Iowa Environmental Mesonet (http://mesonet.agron.iastate.edu/). Arrows indicate the first ‘cold-shock’ day of each growing season.
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Figure 1: Miscanthus × giganteus senescence response to date and average daily temperature. Net CO2 assimilation rate (A, μmol m–2 s–1) (A, B), photosystem II efficiency (ΦPSII, dimensionless) (C, D), and total leaf N ([N], %) (E, F) were measured in autumn 2010 (A, C, E) and 2011 (B, D, F). Measurements were made on two randomly chosen plants per plot and were averaged within eight plots for first-year (closed circles), second-year (closed squares) and third-year (closed triangles) M. × giganteus on each date. Points plotted indicate the mean of these eight (n=8) observations within each stand age and date combination. Error bars indicate ±1 standard error of the mean. Average daily temperatures (solid line) and daily low temperatures (dotted line) were recorded at an adjacent (6.3 km NE) weather station and acquired from the Iowa Environmental Mesonet (http://mesonet.agron.iastate.edu/). Arrows indicate the first ‘cold-shock’ day of each growing season.

Mentions: In this study, first-year M. × giganteus maintained greater photosynthetic capacity during late autumn than second- and third-year M. × giganteus as evidenced by a greater rebound in photosynthetic rates and ΦPSII in the days following a ‘cold-shock’ (days with temperature averages of <10 °C; Fig. 1). In addition, second- and third-year M. × giganteus typically maintained lower photosynthetic rates and leaf [N] throughout autumn until a killing frost. Leaf [N] differences between stand ages were apparent early in the autumn, especially in 2011 when measurements probably commenced too late to capture any divergence between stand ages. Regression analysis showed that the relationship (slopes) of gs and A was slightly different in first and second-year plants in 2010 (P <0.0001), but in 2011 when photosynthetic differences were more pronounced between the different stand ages, there were no differences in the relationship of gs and A (P=0.1600; Fig. 2).


Autumnal leaf senescence in Miscanthus × giganteus and leaf [N] differ by stand age.

Boersma NN, Dohleman FG, Miguez FE, Heaton EA - J. Exp. Bot. (2015)

Miscanthus × giganteus senescence response to date and average daily temperature. Net CO2 assimilation rate (A, μmol m–2 s–1) (A, B), photosystem II efficiency (ΦPSII, dimensionless) (C, D), and total leaf N ([N], %) (E, F) were measured in autumn 2010 (A, C, E) and 2011 (B, D, F). Measurements were made on two randomly chosen plants per plot and were averaged within eight plots for first-year (closed circles), second-year (closed squares) and third-year (closed triangles) M. × giganteus on each date. Points plotted indicate the mean of these eight (n=8) observations within each stand age and date combination. Error bars indicate ±1 standard error of the mean. Average daily temperatures (solid line) and daily low temperatures (dotted line) were recorded at an adjacent (6.3 km NE) weather station and acquired from the Iowa Environmental Mesonet (http://mesonet.agron.iastate.edu/). Arrows indicate the first ‘cold-shock’ day of each growing season.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4493784&req=5

Figure 1: Miscanthus × giganteus senescence response to date and average daily temperature. Net CO2 assimilation rate (A, μmol m–2 s–1) (A, B), photosystem II efficiency (ΦPSII, dimensionless) (C, D), and total leaf N ([N], %) (E, F) were measured in autumn 2010 (A, C, E) and 2011 (B, D, F). Measurements were made on two randomly chosen plants per plot and were averaged within eight plots for first-year (closed circles), second-year (closed squares) and third-year (closed triangles) M. × giganteus on each date. Points plotted indicate the mean of these eight (n=8) observations within each stand age and date combination. Error bars indicate ±1 standard error of the mean. Average daily temperatures (solid line) and daily low temperatures (dotted line) were recorded at an adjacent (6.3 km NE) weather station and acquired from the Iowa Environmental Mesonet (http://mesonet.agron.iastate.edu/). Arrows indicate the first ‘cold-shock’ day of each growing season.
Mentions: In this study, first-year M. × giganteus maintained greater photosynthetic capacity during late autumn than second- and third-year M. × giganteus as evidenced by a greater rebound in photosynthetic rates and ΦPSII in the days following a ‘cold-shock’ (days with temperature averages of <10 °C; Fig. 1). In addition, second- and third-year M. × giganteus typically maintained lower photosynthetic rates and leaf [N] throughout autumn until a killing frost. Leaf [N] differences between stand ages were apparent early in the autumn, especially in 2011 when measurements probably commenced too late to capture any divergence between stand ages. Regression analysis showed that the relationship (slopes) of gs and A was slightly different in first and second-year plants in 2010 (P <0.0001), but in 2011 when photosynthetic differences were more pronounced between the different stand ages, there were no differences in the relationship of gs and A (P=0.1600; Fig. 2).

Bottom Line: By the end of the growing season, first-year M. × giganteus had A and ΦPSII rates up to 4 times greater than third-year M. × giganteus, while leaf [N] was up to 2.4 times greater.The increased photosynthetic capability and leaf N status in first-year M. × giganteus suggests that the photosynthetic apparatus was not dismantled before a killing frost, thus potentially limiting nutrient translocation, and may explain why young M. × giganteus stands do not survive winter when older stands do.Because previous senescence research has primarily focused on annual or woody species, our results suggest that M. × giganteus may be an interesting herbaceous perennial system to investigate the interactive effects of plant ageing and nutrient status on senescence and may highlight management strategies that could potentially increase winter survival rates in first-year stands.

View Article: PubMed Central - PubMed

Affiliation: Department of Agronomy, Iowa State University, Ames, IA 50011, USA.

No MeSH data available.


Related in: MedlinePlus