Limits...
Ecophysiological and anatomical mechanisms behind the nurse effect: which are more important? A multivariate approach for cactus seedlings.

Delgado-Sánchez P, Yáñez-Espinosa L, Jiménez-Bremont JF, Chapa-Vargas L, Flores J - PLoS ONE (2013)

Bottom Line: In addition, the chloroplasts of cells under high-light and non-watering treatment were clumped closer to the center of the cytosol than those under shade-drought, to avoid photoinhibition and/or to better distribute or utilize the penetrating light in the green plant tissue.Opuntia seedlings grow better under the shade, although they can tolerate drought in open spaces by increasing and moving chloroplasts and avoiding drastic decreases in their Ψs .This tolerance could have important implications for predicting the impact of climate change on natural desert regeneration, as well as for planning reforestation-afforestation practices, and rural land uses.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Agronomía y Veterinaria, Universidad Autónoma de San Luis Potosí, Soledad de Graciano Sánchez, México.

ABSTRACT

Background: Cacti establish mostly occurs under the canopy of nurse plants which provide a less stressful micro-environment, although mechanisms underlying this process are unknown. The impact of the combination of light and watering treatments on Opuntia streptacantha (Cactaceae) seedlings was examined.

Methods/principal findings: Ecophysiological [titratable acidity, osmotic potential ('solute potential', Ψs ), relative growth rate (RGR) and their components (NAR, SLA, and LWR)], anatomical (chloroplast density, chloroplast frequency, and cell area), and environmental [photosynthetic photon flux density (PPFD) and air temperature] sets of variables were analyzed, assessing relationships between them and measuring the intensity of the relationships. Three harvests were carried out at days 15, 30, and 45. Ψs and acidity content were the most important responses for seedling establishment. The main anatomical and environmental variables were chloroplast density and water availability, respectively. Opuntia streptacantha seedlings establish better in the shade-watering treatment, due to higher Ψs and acidity, unaffected chloroplasts, and lower PPFD. In addition, the chloroplasts of cells under high-light and non-watering treatment were clumped closer to the center of the cytosol than those under shade-drought, to avoid photoinhibition and/or to better distribute or utilize the penetrating light in the green plant tissue.

Conclusions: Opuntia seedlings grow better under the shade, although they can tolerate drought in open spaces by increasing and moving chloroplasts and avoiding drastic decreases in their Ψs . This tolerance could have important implications for predicting the impact of climate change on natural desert regeneration, as well as for planning reforestation-afforestation practices, and rural land uses.

Show MeSH

Related in: MedlinePlus

Responses of Opuntia streptacantha seedlings under combined water and light treatments at 15, 30 and 45 days.a) Relative growth rate (RGR; g g−l day−1); b) specific photosynthetic structure area (SPSA; cm2 g−1); c) leaf weight ratio (LWR; g g−l), and d) net assimilation rate (NAR; g cm−2 day−1). Bars represent the means ±SE (P<0.001; n = 3).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3842958&req=5

pone-0081513-g003: Responses of Opuntia streptacantha seedlings under combined water and light treatments at 15, 30 and 45 days.a) Relative growth rate (RGR; g g−l day−1); b) specific photosynthetic structure area (SPSA; cm2 g−1); c) leaf weight ratio (LWR; g g−l), and d) net assimilation rate (NAR; g cm−2 day−1). Bars represent the means ±SE (P<0.001; n = 3).

Mentions: RGR and NAR were not important to the canonical functions, but they also were affected by drought, high solar radiation, and time (P<0.001; Figure 3). The lowest RGR was found under combined drought and both high- and low- solar radiation treatments at days 15, 30 and 45. This also provided the highest RGR under combined watering and low solar radiation treatments at days 15, 30 and 45, as well as under watering and high solar radiation at day 15. The highest NAR was found under watering and low-light intensity at days 30 and 45.


Ecophysiological and anatomical mechanisms behind the nurse effect: which are more important? A multivariate approach for cactus seedlings.

Delgado-Sánchez P, Yáñez-Espinosa L, Jiménez-Bremont JF, Chapa-Vargas L, Flores J - PLoS ONE (2013)

Responses of Opuntia streptacantha seedlings under combined water and light treatments at 15, 30 and 45 days.a) Relative growth rate (RGR; g g−l day−1); b) specific photosynthetic structure area (SPSA; cm2 g−1); c) leaf weight ratio (LWR; g g−l), and d) net assimilation rate (NAR; g cm−2 day−1). Bars represent the means ±SE (P<0.001; n = 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3842958&req=5

pone-0081513-g003: Responses of Opuntia streptacantha seedlings under combined water and light treatments at 15, 30 and 45 days.a) Relative growth rate (RGR; g g−l day−1); b) specific photosynthetic structure area (SPSA; cm2 g−1); c) leaf weight ratio (LWR; g g−l), and d) net assimilation rate (NAR; g cm−2 day−1). Bars represent the means ±SE (P<0.001; n = 3).
Mentions: RGR and NAR were not important to the canonical functions, but they also were affected by drought, high solar radiation, and time (P<0.001; Figure 3). The lowest RGR was found under combined drought and both high- and low- solar radiation treatments at days 15, 30 and 45. This also provided the highest RGR under combined watering and low solar radiation treatments at days 15, 30 and 45, as well as under watering and high solar radiation at day 15. The highest NAR was found under watering and low-light intensity at days 30 and 45.

Bottom Line: In addition, the chloroplasts of cells under high-light and non-watering treatment were clumped closer to the center of the cytosol than those under shade-drought, to avoid photoinhibition and/or to better distribute or utilize the penetrating light in the green plant tissue.Opuntia seedlings grow better under the shade, although they can tolerate drought in open spaces by increasing and moving chloroplasts and avoiding drastic decreases in their Ψs .This tolerance could have important implications for predicting the impact of climate change on natural desert regeneration, as well as for planning reforestation-afforestation practices, and rural land uses.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Agronomía y Veterinaria, Universidad Autónoma de San Luis Potosí, Soledad de Graciano Sánchez, México.

ABSTRACT

Background: Cacti establish mostly occurs under the canopy of nurse plants which provide a less stressful micro-environment, although mechanisms underlying this process are unknown. The impact of the combination of light and watering treatments on Opuntia streptacantha (Cactaceae) seedlings was examined.

Methods/principal findings: Ecophysiological [titratable acidity, osmotic potential ('solute potential', Ψs ), relative growth rate (RGR) and their components (NAR, SLA, and LWR)], anatomical (chloroplast density, chloroplast frequency, and cell area), and environmental [photosynthetic photon flux density (PPFD) and air temperature] sets of variables were analyzed, assessing relationships between them and measuring the intensity of the relationships. Three harvests were carried out at days 15, 30, and 45. Ψs and acidity content were the most important responses for seedling establishment. The main anatomical and environmental variables were chloroplast density and water availability, respectively. Opuntia streptacantha seedlings establish better in the shade-watering treatment, due to higher Ψs and acidity, unaffected chloroplasts, and lower PPFD. In addition, the chloroplasts of cells under high-light and non-watering treatment were clumped closer to the center of the cytosol than those under shade-drought, to avoid photoinhibition and/or to better distribute or utilize the penetrating light in the green plant tissue.

Conclusions: Opuntia seedlings grow better under the shade, although they can tolerate drought in open spaces by increasing and moving chloroplasts and avoiding drastic decreases in their Ψs . This tolerance could have important implications for predicting the impact of climate change on natural desert regeneration, as well as for planning reforestation-afforestation practices, and rural land uses.

Show MeSH
Related in: MedlinePlus