Abstract
This study reports on the effects of water deficits on photosynthesis, plant growth and carbon allocation in the wild sunflower Helianthus petiolaris and in the cultivated sunflower Helianthus annuus grown under controlled conditions in the glasshouse. Water deficits reduced the rate of net photosynthesis and the dry weight of leaves, stems, roots and reproductive parts in both species. The root-to-shoot ratio of about 0.05 in H. petiolaris was lower than the root-to-shoot ratio of about 0.15 in H. annuus. Water stress did not affect the root-to-shoot ratio, but increased the percentage of roots at depth in H. annuus. The decrease in growth induced by water deficits was a consequence of a reduction in both leaf area production and net photosynthesis. Flowering occurred earlier in H. petiolaris than in H. annuus with a consequent earlier allocation of carbon to reproductive parts in the wild compared to the cultivated sunflower. The time to budding and flowering of either species was not altered by mild water stress, but was delayed by severe water deficits. During mild water stress carbon allocation to stems decreased, but that to reproductive parts increased. When plants were severely stressed and then rewatered the proportion af carbon allocated to leaves increased and the proportion allocated to stems decreased when compared to unstressed plants. The adaptative role of these features is discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 181-187 |
| Number of pages | 7 |
| Journal | Oecologia |
| Volume | 69 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - May 1986 |
| Externally published | Yes |
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Photosynthesis, dry matter accumulation and distribution in the wild sunflower Helianthus petiolaris and the cultivated sunflower Helianthus annuus as influenced by water deficits. / Sobrado, M. A.; Turner, Neil C.
In: Oecologia, Vol. 69, No. 2, 05.1986, p. 181-187.Research output: Contribution to journal › Article
TY - JOUR
T1 - Photosynthesis, dry matter accumulation and distribution in the wild sunflower Helianthus petiolaris and the cultivated sunflower Helianthus annuus as influenced by water deficits
AU - Sobrado, M. A.
AU - Turner, Neil C.
PY - 1986/5
Y1 - 1986/5
N2 - This study reports on the effects of water deficits on photosynthesis, plant growth and carbon allocation in the wild sunflower Helianthus petiolaris and in the cultivated sunflower Helianthus annuus grown under controlled conditions in the glasshouse. Water deficits reduced the rate of net photosynthesis and the dry weight of leaves, stems, roots and reproductive parts in both species. The root-to-shoot ratio of about 0.05 in H. petiolaris was lower than the root-to-shoot ratio of about 0.15 in H. annuus. Water stress did not affect the root-to-shoot ratio, but increased the percentage of roots at depth in H. annuus. The decrease in growth induced by water deficits was a consequence of a reduction in both leaf area production and net photosynthesis. Flowering occurred earlier in H. petiolaris than in H. annuus with a consequent earlier allocation of carbon to reproductive parts in the wild compared to the cultivated sunflower. The time to budding and flowering of either species was not altered by mild water stress, but was delayed by severe water deficits. During mild water stress carbon allocation to stems decreased, but that to reproductive parts increased. When plants were severely stressed and then rewatered the proportion af carbon allocated to leaves increased and the proportion allocated to stems decreased when compared to unstressed plants. The adaptative role of these features is discussed.
AB - This study reports on the effects of water deficits on photosynthesis, plant growth and carbon allocation in the wild sunflower Helianthus petiolaris and in the cultivated sunflower Helianthus annuus grown under controlled conditions in the glasshouse. Water deficits reduced the rate of net photosynthesis and the dry weight of leaves, stems, roots and reproductive parts in both species. The root-to-shoot ratio of about 0.05 in H. petiolaris was lower than the root-to-shoot ratio of about 0.15 in H. annuus. Water stress did not affect the root-to-shoot ratio, but increased the percentage of roots at depth in H. annuus. The decrease in growth induced by water deficits was a consequence of a reduction in both leaf area production and net photosynthesis. Flowering occurred earlier in H. petiolaris than in H. annuus with a consequent earlier allocation of carbon to reproductive parts in the wild compared to the cultivated sunflower. The time to budding and flowering of either species was not altered by mild water stress, but was delayed by severe water deficits. During mild water stress carbon allocation to stems decreased, but that to reproductive parts increased. When plants were severely stressed and then rewatered the proportion af carbon allocated to leaves increased and the proportion allocated to stems decreased when compared to unstressed plants. The adaptative role of these features is discussed.
UR - http://www.scopus.com/inward/record.url?scp=0022848231&partnerID=8YFLogxK
U2 - 10.1007/BF00377619
DO - 10.1007/BF00377619
M3 - Article
VL - 69
SP - 181
EP - 187
JO - Oecologia
JF - Oecologia
SN - 0029-8549
IS - 2
ER -