Transcript JA Treatment

Height and Biomass of a Barley - Soybean Rotation Subjected to Gibberellic and Jasmonic Acid Treatments
Matthew Johnson, Hunter Porter, Anna Graves, Jonna Whetsel, Matthew Naifeh, Dillon McDaniel, and Jim Bidlack
Department of Biology, University of Central Oklahoma, 100 N. University Drive, Edmond, Oklahoma 73034
Abstract
An experiment was conducted using gibberellic acid (GA), jasmonic
acid (JA), and combinations thereof, to determine their potential in
altering height and biomass of barley (Hordeum vulgare L.) grown
during the winter, followed by soybean [Glycine max (L.) Merr.]
grown during the summer. Treatments included 0.0 mM, 0.5 mM, 1.5
mM, and 3.0 mM applications of GA and JA, and combinations
thereof, applied exogenously shortly after emergence for barley
during the winter/spring and soybean during the summer/fall growing
seasons. Plants were harvested at maturity and several measurements,
including plant height, and weight of plant and plant components,
were taken to assess responses to treatments. In general, GA
increased height of soybean and JA decreased height of both barley
and soybean. Although there were few significant differences among
treatments in plant biomass, a trend demonstrated that JA consistently
decreased biomass in both species. These results suggest that that GA
and JA can be used to manipulate height in barley and soybean
without substantial loss in biomass yield.
Soil: The soil was prepared by creating a 1:1 composition of Miracle
Gro brand potting soil and peat moss. To prevent soil loss, small
stones were placed in the bottom of the pots near the opening.
Table 2. Average height (cm) of barley plants in response to gibberellic acid (GA)
and jasmonic acid (JA) treatments.
-------------------------- JA Treatment -------------------------GA Treatment 0 mM
0.5 mM
1.5 mM
3.0 mM
0 mM
34.1 a†
31.6 ab
30.9 ab
31.5 ab
0.5 mM
30.8 ab
30.3 b
28.8 bc
29.8 b
1.5 mM
32.0 ab
31.9 ab
30.0 b
30.1 b
3.0 mM
29.6 b
30.9 ab
26.1 c
29.8 b
Fig. 1: Measurement of Soybean Height
Introduction
Table 1. Significance by analysis of variance of barley height (HEIGHT)
and total dry weight (DW).
Source
Treat
Rep
Error
df
15
3
45
HEIGHT
*
**
DW
NS
NS
*, ** Significant at the 0.05 and 0.01 probability levels, respectively.
NS=Not Significant.
Materials and Methods
Pots: Seeds were germinated in and plants were grown in 12-inch
terracotta pots on the roof of the Science Building at the University of
Central Oklahoma, Edmond, Oklahoma. The earthenware pots wick
away moisture from the soil, which simulates drought conditions
more effectively. Plants were watered once every two days, and any
weeds found were removed. Due to the location of the experiment,
there were not many herbivorous insects present to cause damage to
the plants.
Source
Treat
Rep
Error
df
15
3
45
HEIGHT
**
**
TOTFW
NS
**
TOTDW
NS
**
PODDW
NS
**
*, ** Significant at the 0.05 and 0.01 probability levels, respectively. NS=Not
Significant.
Results and Discussion
There was a significant difference in height of the barley plants, with
either gibberellins or jasmonins having the effect of decreasing barley
height (see Table 2). Treatments of 3.0 millimolar gibberellic acid
(GA) with 1.5 millimolar jasmonic (JA) acid produced the shortest
plants on average, while the control for the experiment produced the
tallest.
Although the analysis of variance demonstrated that there were no
significant changes in biomass of barley from treatments, the least
significant difference test revealed that high concentrations of GA
decreased dry biomass (see Table 3). There was also found to be no
significant difference between those plants treated with JA, though
there was a generalized trend of lower biomasses in plants that had
been treated with both GA and JA.
† Means followed by the same letter are not significantly different.
Sowing: The experiment included plants grown in the large pots, with
four replications for each of the sixteen treatments, which were
arranged as a randomized complete block design on the roof of the
Science Building. For barley, all pots were seeded with ~50 seeds on
September 15 2011, with sixteen different types of treatment,
including the control. For soybeans, pots were seeded with 20 seeds at
even spacing on June 14 2012. Once the soybeans had germinated and
allowed to grow, plants were thinned out until the three largest plants
remained in a pot.
Limited precipitation during the summer, coupled with high
temperature, limits the production of food crops and energy crops in
the Southern Great Plains. There is potential for use of some plant
growth regulators (PGRs) such as jasmonic acid, or gibberellic acid,
known to increase yield and growth of plant material (Bidlack and
Buxton 1995), to provide drought tolerance under extreme conditions.
However, limited information is available in the literature to
demonstrate how exogenous applications of JA and other PGRs can
be used to promote crop production under drought conditions
(Hassanein et. al. 2009, Hamayun et. al. 2001). This investigation
evaluates the use of JA, in combination with gibberellic acid, in
altering growth and biomass yield of barley and soybean grown as a
grass-legume rotation in Oklahoma.
Table 4. Significance by analysis of soybean height (HEIGHT), total fresh weight
(TOTFW), total dry weight (TOTDW), and pod dry weight (PODDW).
Unlike barley, soybeans demonstrated a significant increase in height
when treated with higher amounts of gibberellins (see Table 5).
Soybean height was not significantly affected by jasmonic acid
treatment, however, there was a generalized trend that demonstrated
some increase in height at the intermediate concentrations of
jasmonins, as the tallest plant was at 3.0 GA and 1.5 JA.
Fig 3: Harvest of Soybeans
While there were no significant differences of soybean dry weight,
there was a generalized trend of GA decreasing biomass. There was
also a trend of JA decreasing the biomass of soybeans (see Table 6).
Table 5. Average height (cm) of soybean plant in response to gibberellic acid (GA)
and jasmonic acid (JA) treatments.
--------------------------- JA Treatment --------------------------GA Treatment 0 mM
0.5 mM
1.5 mM
3.0 mM
0 mM
42.383 cde† 38.468 de
41.235 cde
38.225 e
0.5 mM
52.610 ab
51.683 ab
50.750 ab
46.095 bcde
1.5 mM
46.275 bcd
53.775 ab
53.668 ab
47.150 bc
3.0 mM
51.240 ab
51.283 ab
55.158 a
52.725 ab
† Means followed by the same letter are not significantly different.
Fig 4: Measurement of Harvest Products
Fig 2: Comparison of Soybean Heights
Treatments: Jasmonic acid (JA) and gibberellic (GA) acid were first
dissolved in deionized water and then mixed with 1% Triton-x
surfactant to help suspend PGRs and to promote absorption by leaf
surfaces. Treatments included 0, 0.5, 1,5, and 3.0 mM JA or GA,
which were applied by a hand sprayer (until saturation) on all parts of
the plant. When undergoing treatment, all plants of the same
treatment of gibberellins were isolated from other gibberellin
treatments, and were placed near each other to ensure that none of the
gibberellin treatment was wasted. Once the water from the gibberellin
treatments had dried, the process was repeated with the jasmonins.
Barley plants were treated in this fashion once in the fall, and once in
the spring. Soybean plants were given one treatment, in the summer.
Table 3. Average total dry weight (g) of barley plants in response to gibberellic acid
(GA) and jasmonic acid (JA) treatments.
-------------------------- JA Treatment -------------------------GA Treatment 0 mM
0.5 mM
1.5 mM
3.0 mM
0 mM
20.4 a†
20.1 abc
19.0 abcd
15.5 abcd
0.5 mM
17.5 abcd
17.0 abcd
16.0 abcd
15.0 bcd
1.5 mM
19.0 abcd
21.5 a
17.5 abcd
13.0 d
3.0 mM
14.0 cd
17.5 abcd
13.0 d
13.3 d
† Means followed by the same letter are not significantly different.
Harvest: Height of soybeans was measured by using a meter stick to
measure from the terminal bud to the base of the plant. These heights
were averaged in order to calculate changes in average height more
quickly. Soybeans were harvested by cutting them approximately 1
cm from the base of plant, and placed in pre-marked bags. The
biomass of the stalk, the leaves, and the pods were measured. Once
weighed, plants were then placed in pre-marked paper sacks and
placed in a drying cabinet for two days. When dried, biomass of stalk,
leaves, and pods were measured again. Height of the barley was
measured by finding an approximate height for the middling plants
and measuring from there, due to the large number of plants per pot.
The barley was harvested by taking a pair of shears and cutting off the
plant approximately 1.0 cm from the base of the plant. Plants were
placed in pre-marked paper bags, and weighed as whole plants, and
heads. Once weighed, the barley was placed in a drying apparatus for
several days. When removed from the apparatus, the dry biomass of
heads and stalks was measured.
Table 6. Average total dry weight (g) of soybean plant in response to gibberellic acid
(GA) and jasmonic acid (JA) treatments.
------------------------- JA Treatment ------------------------GA Treatment 0 mM
0.5 mM
1.5 mM
3.0 mM
0 mM
24.318 a†
19.325 a
20.873 a
19.833 a
0.5 mM
20.290 a
24.440 a
19.210 a
17.935 a
1.5 mM
19.428 a
20.138 a
25.073 a
18.315 a
3.0 mM
21.195 a
21.368 a
19.530 a
19.833 a
† Means followed by the same letter are not significantly different.
Conclusions
The lack of mass increase in the heads of barley and pods of soybeans
from any treatment of gibberellins or jasmonins leads to the
conclusion that these are not effective at increasing yield of food
crops. There may be some use of either gibberellins or jasmonins in
the retardation of growth in grasses, as shown by the height decrease
in barley, though whether this indicative of a similar results in other
plants would need to be studied further.
References
Bidlack, J.E., and D.R. Buxton. 1995. Chemical Regulation of Growth,
Yield, and Digestibility of Alfalfa and Smooth Bromegrass. J Plant
Growth Reg 14:1-7
Hamayun, M., S. Khan, A Khan, J. Shin, B Ahmad, D. Shin and I. Lee.
2010. Exogenous Gibberellic Acid Reprograms Soybean to Higher
Growth and Salt Stress Tolerance. J Agricult Food Chem 58:7226-7232
Hassanein, R., A. Hassanein, A. El-Din, M. Salama, H. Hashem. 2009.
Role of Jasmonic Acid and Abscisic Acid Treatments in Alleviating the
Adverse Effects of Drought Stress and Regulating Trypsin Inhibitor
Production in Soybean Plant. Aust J Basic and Appl Sci 3:904-919
Acknowledgements
Funding for this project was provided by the University of Central
Oklahoma CURE-STEM program and Office of Research & Grants.
Many thanks to Johnston Seed Company, Enid, OK, for donation of
barley seed, and to Ross Seed Company, El Reno, OK, for providing the
soybean seed. We also thank volunteers from Dr. Bidlack’s Research
Group for their participation on this project.