Contribution of photosynthetic rate to growth and reproduction in Amaranthus hybridus

A. Michele Arntz, Evan H Delucia, Nicholas Jordan

Research output: Contribution to journalArticle

Abstract

While it is known that genetic variation for photosynthetic and growth traits exists in natural populations, the functional significance of this variation remains unclear, particularly for photosynthetic traits. To test the hypothesis that photosynthetic rate has direct effects on reproduction as well as contributing indirectly to reproduction through effects on growth, we compared wild-type Amaranthus hybridus families to those with a single gene mutation that confers a lower photosynthetic rate. Wild-type and photosynthetic-mutant families were grown in competitive and non-competitive environments and we compared size, biomass allocation, architecture, and reproduction at three developmental stages. To assess the contributions of individual growth traits to reproduction, we calculated covariances between standardized traits and relative fitness (selection differentials), and compared selection between the two biotypes. Finally, we used path analysis to calculate the indirect effects of photosynthetic rate on fitness through growth. The size, allocation, and architecture of photosynthetic mutants did not differ from those of the wild type in either the competitive or non-competitive environment, with the exception that they were taller by the last developmental stage. However, the reproductive biomass of the photosynthetic mutants was significantly reduced compared to the wild type. In the competitive environment, the wild type achieved greater fitness because, while similar in size to the mutants, at any given size it produced more reproductive biomass. This suggests that photosynthetic rate affected the linkage between plant size and reproduction and is evidence of an indirect contribution to fitness. In the non-competitive environment, there were fewer differences in selection differentials between the two plant genotypes, suggesting fewer indirect effects. Path analysis showed that variation in photosynthetic biotype had indirect effects on reproductive biomass, via growth traits, and that there were no direct effects. Photosynthetic rate appears to have fitness consequences primarily through multiple contributions to growth throughout development.

Original languageEnglish (US)
Pages (from-to)323-330
Number of pages8
JournalOecologia
Volume117
Issue number3
DOIs
StatePublished - Dec 1 1998

Fingerprint

Amaranthus hybridus
fitness
growth traits
mutants
biotype
biotypes
path analysis
biomass
developmental stage
developmental stages
dry matter partitioning
biomass allocation
linkage (genetics)
effect
rate
genetic variation
mutation
genotype
mutant
gene

Keywords

  • Atrazine
  • Fitness
  • Path analysis
  • Photosynthesis
  • Resistance
  • Selection

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Contribution of photosynthetic rate to growth and reproduction in Amaranthus hybridus. / Arntz, A. Michele; Delucia, Evan H; Jordan, Nicholas.

In: Oecologia, Vol. 117, No. 3, 01.12.1998, p. 323-330.

Research output: Contribution to journalArticle

Arntz, A. Michele ; Delucia, Evan H ; Jordan, Nicholas. / Contribution of photosynthetic rate to growth and reproduction in Amaranthus hybridus. In: Oecologia. 1998 ; Vol. 117, No. 3. pp. 323-330.
@article{a64d016661214abfb721a3c34c8ddefa,
title = "Contribution of photosynthetic rate to growth and reproduction in Amaranthus hybridus",
abstract = "While it is known that genetic variation for photosynthetic and growth traits exists in natural populations, the functional significance of this variation remains unclear, particularly for photosynthetic traits. To test the hypothesis that photosynthetic rate has direct effects on reproduction as well as contributing indirectly to reproduction through effects on growth, we compared wild-type Amaranthus hybridus families to those with a single gene mutation that confers a lower photosynthetic rate. Wild-type and photosynthetic-mutant families were grown in competitive and non-competitive environments and we compared size, biomass allocation, architecture, and reproduction at three developmental stages. To assess the contributions of individual growth traits to reproduction, we calculated covariances between standardized traits and relative fitness (selection differentials), and compared selection between the two biotypes. Finally, we used path analysis to calculate the indirect effects of photosynthetic rate on fitness through growth. The size, allocation, and architecture of photosynthetic mutants did not differ from those of the wild type in either the competitive or non-competitive environment, with the exception that they were taller by the last developmental stage. However, the reproductive biomass of the photosynthetic mutants was significantly reduced compared to the wild type. In the competitive environment, the wild type achieved greater fitness because, while similar in size to the mutants, at any given size it produced more reproductive biomass. This suggests that photosynthetic rate affected the linkage between plant size and reproduction and is evidence of an indirect contribution to fitness. In the non-competitive environment, there were fewer differences in selection differentials between the two plant genotypes, suggesting fewer indirect effects. Path analysis showed that variation in photosynthetic biotype had indirect effects on reproductive biomass, via growth traits, and that there were no direct effects. Photosynthetic rate appears to have fitness consequences primarily through multiple contributions to growth throughout development.",
keywords = "Atrazine, Fitness, Path analysis, Photosynthesis, Resistance, Selection",
author = "Arntz, {A. Michele} and Delucia, {Evan H} and Nicholas Jordan",
year = "1998",
month = "12",
day = "1",
doi = "10.1007/s004420050665",
language = "English (US)",
volume = "117",
pages = "323--330",
journal = "Oecologia",
issn = "0029-8519",
publisher = "Springer Verlag",
number = "3",

}

TY - JOUR

T1 - Contribution of photosynthetic rate to growth and reproduction in Amaranthus hybridus

AU - Arntz, A. Michele

AU - Delucia, Evan H

AU - Jordan, Nicholas

PY - 1998/12/1

Y1 - 1998/12/1

N2 - While it is known that genetic variation for photosynthetic and growth traits exists in natural populations, the functional significance of this variation remains unclear, particularly for photosynthetic traits. To test the hypothesis that photosynthetic rate has direct effects on reproduction as well as contributing indirectly to reproduction through effects on growth, we compared wild-type Amaranthus hybridus families to those with a single gene mutation that confers a lower photosynthetic rate. Wild-type and photosynthetic-mutant families were grown in competitive and non-competitive environments and we compared size, biomass allocation, architecture, and reproduction at three developmental stages. To assess the contributions of individual growth traits to reproduction, we calculated covariances between standardized traits and relative fitness (selection differentials), and compared selection between the two biotypes. Finally, we used path analysis to calculate the indirect effects of photosynthetic rate on fitness through growth. The size, allocation, and architecture of photosynthetic mutants did not differ from those of the wild type in either the competitive or non-competitive environment, with the exception that they were taller by the last developmental stage. However, the reproductive biomass of the photosynthetic mutants was significantly reduced compared to the wild type. In the competitive environment, the wild type achieved greater fitness because, while similar in size to the mutants, at any given size it produced more reproductive biomass. This suggests that photosynthetic rate affected the linkage between plant size and reproduction and is evidence of an indirect contribution to fitness. In the non-competitive environment, there were fewer differences in selection differentials between the two plant genotypes, suggesting fewer indirect effects. Path analysis showed that variation in photosynthetic biotype had indirect effects on reproductive biomass, via growth traits, and that there were no direct effects. Photosynthetic rate appears to have fitness consequences primarily through multiple contributions to growth throughout development.

AB - While it is known that genetic variation for photosynthetic and growth traits exists in natural populations, the functional significance of this variation remains unclear, particularly for photosynthetic traits. To test the hypothesis that photosynthetic rate has direct effects on reproduction as well as contributing indirectly to reproduction through effects on growth, we compared wild-type Amaranthus hybridus families to those with a single gene mutation that confers a lower photosynthetic rate. Wild-type and photosynthetic-mutant families were grown in competitive and non-competitive environments and we compared size, biomass allocation, architecture, and reproduction at three developmental stages. To assess the contributions of individual growth traits to reproduction, we calculated covariances between standardized traits and relative fitness (selection differentials), and compared selection between the two biotypes. Finally, we used path analysis to calculate the indirect effects of photosynthetic rate on fitness through growth. The size, allocation, and architecture of photosynthetic mutants did not differ from those of the wild type in either the competitive or non-competitive environment, with the exception that they were taller by the last developmental stage. However, the reproductive biomass of the photosynthetic mutants was significantly reduced compared to the wild type. In the competitive environment, the wild type achieved greater fitness because, while similar in size to the mutants, at any given size it produced more reproductive biomass. This suggests that photosynthetic rate affected the linkage between plant size and reproduction and is evidence of an indirect contribution to fitness. In the non-competitive environment, there were fewer differences in selection differentials between the two plant genotypes, suggesting fewer indirect effects. Path analysis showed that variation in photosynthetic biotype had indirect effects on reproductive biomass, via growth traits, and that there were no direct effects. Photosynthetic rate appears to have fitness consequences primarily through multiple contributions to growth throughout development.

KW - Atrazine

KW - Fitness

KW - Path analysis

KW - Photosynthesis

KW - Resistance

KW - Selection

UR - http://www.scopus.com/inward/record.url?scp=0032409488&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032409488&partnerID=8YFLogxK

U2 - 10.1007/s004420050665

DO - 10.1007/s004420050665

M3 - Article

AN - SCOPUS:0032409488

VL - 117

SP - 323

EP - 330

JO - Oecologia

JF - Oecologia

SN - 0029-8519

IS - 3

ER -