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A rootstock provides water conservation for a grafted commercial tomato (Solanum lycopersicum L.) line in response to mild-drought conditions: a focus on vegetative growth and photosynthetic parameters.

Nilsen ET, Freeman J, Grene R, Tokuhisa J - PLoS ONE (2014)

Bottom Line: Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought.Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance.Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America.

ABSTRACT
The development of water stress resistant lines of commercial tomato by breeding or genetic engineering is possible, but will take considerable time before commercial varieties are available for production. However, grafting commercial tomato lines on drought resistant rootstock may produce drought tolerant commercial tomato lines much more rapidly. Due to changing climates and the need for commercial production of vegetables in low quality fields there is an urgent need for stress tolerant commercial lines of vegetables such as tomato. In previous observations we identified a scion root stock combination ('BHN 602' scion grafted onto 'Jjak Kkung' rootstock hereafter identified as 602/Jjak) that had a qualitative drought-tolerance phenotype when compared to the non-grafted line. Based on this initial observation, we studied photosynthesis and vegetative above-ground growth during mild-drought for the 602/Jjak compared with another scion-rootstock combination ('BHN 602' scion grafted onto 'Cheong Gang' rootstock hereafter identified as 602/Cheong) and a non-grafted control. Overall above ground vegetative growth was significantly lower for 602/Jjak in comparison to the other plant lines. Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought. Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance. Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought. These data show that different rootstocks can change the photosynthetic responses to drought of a high yielding, commercial tomato line. Also, this rapid discovery of one scion-rootstock combination that provided mild-drought tolerance suggests that screening more scion-rootstock combination for stress tolerance may rapidly yield commercially viable, stress tolerant lines of tomato.

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Mean midday water potential (A, B, C) and midday stomatal conductance (D, E, F) for three different lines of tomato grown with daily watering (control) or daily watering until water was withheld between day 20 and day 28 (mild-drought treatment).602 = ‘BHN 602’; 602/Cheong  =  refers to line ‘BHN 602’ scion grafted onto ‘Cheong Gang’ rootstock; 602/Jjak refers to line ‘BHN 602’ scion grafted onto ‘Jjak Kkung’ rootstock. Error bars represent two standard errors on each side of the mean. *  =  significant difference between control and mild-drought treated plants within a plant type (Student's t-test; p<0.05).
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pone-0115380-g004: Mean midday water potential (A, B, C) and midday stomatal conductance (D, E, F) for three different lines of tomato grown with daily watering (control) or daily watering until water was withheld between day 20 and day 28 (mild-drought treatment).602 = ‘BHN 602’; 602/Cheong  =  refers to line ‘BHN 602’ scion grafted onto ‘Cheong Gang’ rootstock; 602/Jjak refers to line ‘BHN 602’ scion grafted onto ‘Jjak Kkung’ rootstock. Error bars represent two standard errors on each side of the mean. *  =  significant difference between control and mild-drought treated plants within a plant type (Student's t-test; p<0.05).

Mentions: Leaf water potentials, of all three lines, ranged from −0.1 MPa to −0.9 MPa between days 5 and 19 of the experimental period, which was most likely due to variation in PPFD and air temperature among days (Fig. 4A-C). Following day 20, control plants continued to vary within the same leaf water potential range for all three lines. Leaf water potential of mild-drought treatment plants decreased from day 20 until day 29 at which time the plants were re-watered. Line 602 decreased to a mean plus one standard deviation of −1.29±0.08 MPa, line 602/Cheong decreased to −1.23±0.16 MPa and line 602/Jjak decreased to −1.13±0.14 MPa during the water-withholding period. Following re-watering on day 29 mild-drought treatment plants of all three lines returned to the control leaf water potential range. The mean minimum water potential for all lines (using the last two days of mild-drought treatment) were not significantly different from each other (Student's two-tailed t-Test, df = 5, P(T< = t) ranged from 0.4736 to 0.2532).


A rootstock provides water conservation for a grafted commercial tomato (Solanum lycopersicum L.) line in response to mild-drought conditions: a focus on vegetative growth and photosynthetic parameters.

Nilsen ET, Freeman J, Grene R, Tokuhisa J - PLoS ONE (2014)

Mean midday water potential (A, B, C) and midday stomatal conductance (D, E, F) for three different lines of tomato grown with daily watering (control) or daily watering until water was withheld between day 20 and day 28 (mild-drought treatment).602 = ‘BHN 602’; 602/Cheong  =  refers to line ‘BHN 602’ scion grafted onto ‘Cheong Gang’ rootstock; 602/Jjak refers to line ‘BHN 602’ scion grafted onto ‘Jjak Kkung’ rootstock. Error bars represent two standard errors on each side of the mean. *  =  significant difference between control and mild-drought treated plants within a plant type (Student's t-test; p<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4274011&req=5

pone-0115380-g004: Mean midday water potential (A, B, C) and midday stomatal conductance (D, E, F) for three different lines of tomato grown with daily watering (control) or daily watering until water was withheld between day 20 and day 28 (mild-drought treatment).602 = ‘BHN 602’; 602/Cheong  =  refers to line ‘BHN 602’ scion grafted onto ‘Cheong Gang’ rootstock; 602/Jjak refers to line ‘BHN 602’ scion grafted onto ‘Jjak Kkung’ rootstock. Error bars represent two standard errors on each side of the mean. *  =  significant difference between control and mild-drought treated plants within a plant type (Student's t-test; p<0.05).
Mentions: Leaf water potentials, of all three lines, ranged from −0.1 MPa to −0.9 MPa between days 5 and 19 of the experimental period, which was most likely due to variation in PPFD and air temperature among days (Fig. 4A-C). Following day 20, control plants continued to vary within the same leaf water potential range for all three lines. Leaf water potential of mild-drought treatment plants decreased from day 20 until day 29 at which time the plants were re-watered. Line 602 decreased to a mean plus one standard deviation of −1.29±0.08 MPa, line 602/Cheong decreased to −1.23±0.16 MPa and line 602/Jjak decreased to −1.13±0.14 MPa during the water-withholding period. Following re-watering on day 29 mild-drought treatment plants of all three lines returned to the control leaf water potential range. The mean minimum water potential for all lines (using the last two days of mild-drought treatment) were not significantly different from each other (Student's two-tailed t-Test, df = 5, P(T< = t) ranged from 0.4736 to 0.2532).

Bottom Line: Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought.Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance.Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America.

ABSTRACT
The development of water stress resistant lines of commercial tomato by breeding or genetic engineering is possible, but will take considerable time before commercial varieties are available for production. However, grafting commercial tomato lines on drought resistant rootstock may produce drought tolerant commercial tomato lines much more rapidly. Due to changing climates and the need for commercial production of vegetables in low quality fields there is an urgent need for stress tolerant commercial lines of vegetables such as tomato. In previous observations we identified a scion root stock combination ('BHN 602' scion grafted onto 'Jjak Kkung' rootstock hereafter identified as 602/Jjak) that had a qualitative drought-tolerance phenotype when compared to the non-grafted line. Based on this initial observation, we studied photosynthesis and vegetative above-ground growth during mild-drought for the 602/Jjak compared with another scion-rootstock combination ('BHN 602' scion grafted onto 'Cheong Gang' rootstock hereafter identified as 602/Cheong) and a non-grafted control. Overall above ground vegetative growth was significantly lower for 602/Jjak in comparison to the other plant lines. Moreover, water potential reduction in response to mild drought was significantly less for 602/Jjak, yet stomatal conductance of all plant-lines were equally inhibited by mild-drought. Light saturated photosynthesis of 602/Jjak was less affected by low water potential than the other two lines as was the % reduction in mesophyll conductance. Therefore, the Jjak Kkung rootstock caused aboveground growth reduction, water conservation and increased photosynthetic tolerance of mild drought. These data show that different rootstocks can change the photosynthetic responses to drought of a high yielding, commercial tomato line. Also, this rapid discovery of one scion-rootstock combination that provided mild-drought tolerance suggests that screening more scion-rootstock combination for stress tolerance may rapidly yield commercially viable, stress tolerant lines of tomato.

Show MeSH
Related in: MedlinePlus