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Are plant growth and photosynthesis limited by pre-drought following rewatering in grass?

Xu Z, Zhou G, Shimizu H - J. Exp. Bot. (2009)

Bottom Line: The results indicated that g(s) may be responsible for regulating actual photosynthetic efficiency.It is assumed that the new plant growth and photosynthetic potential enhanced by pre-drought following rewatering may try to overcompensate the great loss of the plant's net primary production due to the pre-drought effect.The present results highlight the episodic effects of drought on grass growth and photosynthesis.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Science, Beijing, PR China.

ABSTRACT
Although the relationship between grassland productivity and soil water status has been extensively researched, the responses of plant growth and photosynthetic physiological processes to long-term drought and rewatering are not fully understood. Here, the perennial grass (Leymus chinensis), predominantly distributed in the Euro-Asia steppe, was used as an experimental plant for an irrigation manipulation experiment involving five soil moisture levels [75-80, 60-75, 50-60, 35-50, and 25-35% of soil relative water content (SRWC), i.e. the ratio between present soil moisture and field capacity] to examine the effects of soil drought and rewatering on plant biomass, relative growth rate (RGR), and photosynthetic potential. The recovery of plant biomass following rewatering was lower for the plants that had experienced previous drought compared with the controls; the extent of recovery was proportional to the intensity of soil drought. However, the plant RGR, leaf photosynthesis, and light use potential were markedly stimulated by the previous drought, depending on drought intensity, whereas stomatal conductance (g(s)) achieved only partial recovery. The results indicated that g(s) may be responsible for regulating actual photosynthetic efficiency. It is assumed that the new plant growth and photosynthetic potential enhanced by pre-drought following rewatering may try to overcompensate the great loss of the plant's net primary production due to the pre-drought effect. The present results highlight the episodic effects of drought on grass growth and photosynthesis. This study will assist in understanding how degraded ecosystems can potentially cope with climate change.

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(A) Relative growth rate (RGR) after rewatering from the continuous soil drought treatment (101 d), and (B) after rewatering from the start of soil drought treatment (81 d). Five SRWCs are indicated by control (75–80%), LD (60–75%), MD (5–60%), SD (35–50%), and ED (25–35%). All values are means ±SE for n=5. Bars with different lowercase letters are significantly different in the same organs (P <0.05).
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fig3: (A) Relative growth rate (RGR) after rewatering from the continuous soil drought treatment (101 d), and (B) after rewatering from the start of soil drought treatment (81 d). Five SRWCs are indicated by control (75–80%), LD (60–75%), MD (5–60%), SD (35–50%), and ED (25–35%). All values are means ±SE for n=5. Bars with different lowercase letters are significantly different in the same organs (P <0.05).

Mentions: The RGR changes in different organs of the plants were measured after rewatering after the continuous soil drought treatment (101 d, Fig. 3A) and after rewatering from the starting soil drought treatment (81 d, Fig. 3B). It was found that the RGR was significantly stimulated by more than SD treatments when the two durations of drought treatments were completed, except for stem and litter organs with the previous long-term drought treatment. For the long-term drought treatment (Fig. 3A), the greatest RGR occurred in root, followed by green leaf; in contrast, for short-term drought (Fig. 3B), the maximum values were in litter, followed by stem and green leaf, possibly due to the lower amount of litter with the short-term drought treatment. Nevertheless, following rewatering, previous SD still caused a significant RGR increase of the whole plant for both durations of soil drought, indicating that plant RGR was remarkably stimulated by the previous SD.


Are plant growth and photosynthesis limited by pre-drought following rewatering in grass?

Xu Z, Zhou G, Shimizu H - J. Exp. Bot. (2009)

(A) Relative growth rate (RGR) after rewatering from the continuous soil drought treatment (101 d), and (B) after rewatering from the start of soil drought treatment (81 d). Five SRWCs are indicated by control (75–80%), LD (60–75%), MD (5–60%), SD (35–50%), and ED (25–35%). All values are means ±SE for n=5. Bars with different lowercase letters are significantly different in the same organs (P <0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2736889&req=5

fig3: (A) Relative growth rate (RGR) after rewatering from the continuous soil drought treatment (101 d), and (B) after rewatering from the start of soil drought treatment (81 d). Five SRWCs are indicated by control (75–80%), LD (60–75%), MD (5–60%), SD (35–50%), and ED (25–35%). All values are means ±SE for n=5. Bars with different lowercase letters are significantly different in the same organs (P <0.05).
Mentions: The RGR changes in different organs of the plants were measured after rewatering after the continuous soil drought treatment (101 d, Fig. 3A) and after rewatering from the starting soil drought treatment (81 d, Fig. 3B). It was found that the RGR was significantly stimulated by more than SD treatments when the two durations of drought treatments were completed, except for stem and litter organs with the previous long-term drought treatment. For the long-term drought treatment (Fig. 3A), the greatest RGR occurred in root, followed by green leaf; in contrast, for short-term drought (Fig. 3B), the maximum values were in litter, followed by stem and green leaf, possibly due to the lower amount of litter with the short-term drought treatment. Nevertheless, following rewatering, previous SD still caused a significant RGR increase of the whole plant for both durations of soil drought, indicating that plant RGR was remarkably stimulated by the previous SD.

Bottom Line: The results indicated that g(s) may be responsible for regulating actual photosynthetic efficiency.It is assumed that the new plant growth and photosynthetic potential enhanced by pre-drought following rewatering may try to overcompensate the great loss of the plant's net primary production due to the pre-drought effect.The present results highlight the episodic effects of drought on grass growth and photosynthesis.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Science, Beijing, PR China.

ABSTRACT
Although the relationship between grassland productivity and soil water status has been extensively researched, the responses of plant growth and photosynthetic physiological processes to long-term drought and rewatering are not fully understood. Here, the perennial grass (Leymus chinensis), predominantly distributed in the Euro-Asia steppe, was used as an experimental plant for an irrigation manipulation experiment involving five soil moisture levels [75-80, 60-75, 50-60, 35-50, and 25-35% of soil relative water content (SRWC), i.e. the ratio between present soil moisture and field capacity] to examine the effects of soil drought and rewatering on plant biomass, relative growth rate (RGR), and photosynthetic potential. The recovery of plant biomass following rewatering was lower for the plants that had experienced previous drought compared with the controls; the extent of recovery was proportional to the intensity of soil drought. However, the plant RGR, leaf photosynthesis, and light use potential were markedly stimulated by the previous drought, depending on drought intensity, whereas stomatal conductance (g(s)) achieved only partial recovery. The results indicated that g(s) may be responsible for regulating actual photosynthetic efficiency. It is assumed that the new plant growth and photosynthetic potential enhanced by pre-drought following rewatering may try to overcompensate the great loss of the plant's net primary production due to the pre-drought effect. The present results highlight the episodic effects of drought on grass growth and photosynthesis. This study will assist in understanding how degraded ecosystems can potentially cope with climate change.

Show MeSH