Root growth and proline content in drought sensitive and tolerant maize (Zea maysL.) seedlings under different water potentials

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.

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Maize seedling performance as a potential index for drought tolerance

Archives of Biological Sciences ◽

10.2298/abs170504036k ◽

2018 ◽

Vol 70 (1) ◽

pp. 167-177

Author(s):

Natalija Kravic ◽

Sukalovic Hadzi-Taskovic ◽

Vojka Babic ◽

Jelena Srdic ◽

Jelena Mesarovic ◽

...

Keyword(s):

Drought Tolerance ◽

Osmotic Stress ◽

Root Growth ◽

Grain Yield ◽

Maize Seedling ◽

Proline Content ◽

Seedling Root ◽

Early Seedling ◽

Positive Correlations ◽

Adult Plants

Twenty-six maize landraces were tested in order to evaluate maize seedling performance as an index for drought tolerance in adult plants. Samples were subjected to polyethylene glycol-induced osmotic stress at the early seedling stage. Grain yield was obtained in field experiments under well-watered (OC) and a combination of drought and high plant density (HD) conditions. Osmotic stress caused a reduction in seedling growth (length, fresh and dry weight), and increase in the shoot and in particular the root proline contents in the majority of landraces, and variations in root peroxidase (POD) activity. Genotypes displaying more pronounced root growth reduction and higher proline contents exhibited decreased POD activity under osmotic stress. Direct positive correlations between the proline content and growth inhibition, and between the proline and soluble protein content were established. Correlations between the changes in POD activity and growth parameters were significant and positive, and significant but negative with the changes in the proline content. In the field, water stress led to a reduction in grain yield in all of the tested landraces. Correlations between grain yield from both experimental sets (OC and HD) and osmotic-induced changes in seedling root growth were negative, which was opposite to the highly significant and positive correlations between the changes in the seedling root proline content and yield. Also, genotypes with the highest seedling root proline content increase under osmotic stress, exhibited the highest stress tolerance index (STI) based on grain yield achieved under both field conditions. Our results indicate that lower changes in POD activity and especially an increased proline content after exposure to osmotic stress during the early seedling stage could be considered as useful indices to facilitate selection efficiency for drought tolerance in adult plants.

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Complexity and coordination of root growth at low water potentials: recent advances from transcriptomic and proteomic analyses

Plant Cell & Environment ◽

10.1111/j.1365-3040.2009.02064.x ◽

2010 ◽

Vol 33 (4) ◽

pp. 590-603 ◽

Cited By ~ 101

Author(s):

MINEO YAMAGUCHI ◽

ROBERT E. SHARP

Keyword(s):

Root Growth ◽

Recent Advances ◽

Water Potentials ◽

Proteomic Analyses

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Development of a root growth model for yellow-poplar and sweetgum seedlings grown in compacted soil

Canadian Journal of Forest Research ◽

10.1139/x88-111 ◽

1988 ◽

Vol 18 (6) ◽

pp. 728-732 ◽

Cited By ~ 3

Author(s):

G. L. Simmons ◽

P. E. Pope

Keyword(s):

Root Growth ◽

Growth Model ◽

Lateral Roots ◽

Soil Conditions ◽

Soil Parameters ◽

Mechanical Resistance ◽

Yellow Poplar ◽

Greenhouse Study ◽

Water Potentials ◽

Loam Soil

A root growth model was developed to graphically simulate predicted root responses of yellow-poplar and sweetgum seedlings to changes in soil physical properties. Data for the model were collected in greenhouse and laboratory experiments. Newly germinated yellow-poplar (Liriodendrontulipifera L.) and sweetgum (Liquidambarstyraciflua L.) seedlings were transplanted into pots containing silt loam soil compacted to bulk densities of 1.25, 1.40, or 1.55 Mg m−3 and grown under greenhouse conditions for 3 months. Minimum water potentials were maintained at −10 or −300 kPa. At harvest, root systems were excavated, divided into orders of lateral roots, and length, number, and branching frequency of each order were determined. Air-filled porosity and mechanical resistance were determined for soil samples equilibrated at the same bulk densities and water potentials as those used in the greenhouse study. Based on root and soil parameters, the model ROOTSIM graphically depicts the root distribution of each tree species at different levels of bulk density, mechanical resistance, and air-filled porosity. The model accurately predicts lateral root length and distribution for the range of soil properties used in the greenhouse study but has not been validated for these or other soil conditions.

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Spatial Distribution of Turgor and Root Growth at Low Water Potentials

PLANT PHYSIOLOGY ◽

10.1104/pp.96.2.438 ◽

1991 ◽

Vol 96 (2) ◽

pp. 438-443 ◽

Cited By ~ 96

Author(s):

William G. Spollen ◽

Robert E. Sharp

Keyword(s):

Spatial Distribution ◽

Root Growth ◽

Water Potentials

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INFLUENCE OF SOIL DENSITY ON LEAF WATER POTENTIAL OF CORN

Canadian Journal of Soil Science ◽

10.4141/cjss78-032 ◽

1978 ◽

Vol 58 (2) ◽

pp. 275-278

Author(s):

D. T. MORRIS ◽

T. B. DAYNARD

Keyword(s):

Root Growth ◽

Water Potential ◽

Bulk Density ◽

Leaf Area ◽

Leaf Water Potential ◽

Soil Bulk Density ◽

Leaf Water ◽

Soil Density ◽

Water Potentials ◽

Corn Plants

Corn plants were grown in growth rooms at 1.2 and 1.4 g cm−3 soil bulk density. Leaf water potentials (LWP) of paired plants of similar leaf area were monitored during 3-day drying cycles. With denser soil, LWP declined more rapidly during light, and increased more slowly during dark intervals because of restricted root growth.

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Physiological aspects of recalcitrance in embryonic axes of Quercus robur L.

Seed Science Research ◽

10.1017/s0960258500001409 ◽

1992 ◽

Vol 2 (4) ◽

pp. 215-221 ◽

Cited By ~ 14

Author(s):

K. M. Poulsen ◽

E. N. Eriksen

Keyword(s):

Water Potential ◽

Quercus Robur ◽

Fold Increase ◽

Proline Content ◽

Short Exposure ◽

Embryonic Axes ◽

Vegetative Tissue ◽

Water Potentials ◽

Orthodox Seeds ◽

Peak Value

AbstractThe sorption isotherm for excised embryonic axes of recalcitrant (i.e. desiccation-sensitive) Quercus robur L. acorns was determined to find the relation between moisture content and water potential. Subsequently, physiological studies on the effect of desiccating the axes to a range of water potentials were undertaken. The respiratory capacity declined steeply after short exposure to water potentials from −5 to −30 MPa. The leachate conductivity increased significantly after exposure to −5 MPa and rose steeply after exposure to between −12 and −40 MPa. Axes were equilibrated at different relative humidities and the proline content showed a 15-fold increase with a peak value at −10 MPa. It was concluded that the critical water potential for initiation of damage was −5 MPa, and that axes accumulated proline as a response to desiccation stress. The embryonic axes from Q. robur behave more like typical vegetative tissue of angiosperms than like orthodox seeds.

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Influence of soil water potential and mycorrhizal colonization on root growth of yellow-poplar and sweet gum seedlings grown in compacted soil

Canadian Journal of Forest Research ◽

10.1139/x88-217 ◽

1988 ◽

Vol 18 (11) ◽

pp. 1392-1396 ◽

Cited By ~ 11

Author(s):

G. L. Simmons ◽

P. E. Pope

Keyword(s):

Root Growth ◽

Water Potential ◽

Bulk Density ◽

Soil Water ◽

Root Length ◽

Soil Water Potential ◽

Mechanical Resistance ◽

Yellow Poplar ◽

Greenhouse Study ◽

Water Potentials

A greenhouse study was conducted to determine the influence of soil water potential and endomycorrhizal fungi on root growth of yellow-poplar (Liriodendrontulipifera L.) and sweet gum (Liquidambarstyraciflua L.) seedlings grown at three soil bulk densities. Silt loam soil was compacted in PVC pots to bulk densities of 1.25 (low), 1.40 (medium), or 1.55 (high) Mg • m−3, and equilibrated at −10 kPa soil water potential. Newly germinated seedlings were transplanted into the pots, inoculated with fungal chlamydospores of Glomusmacrocarpum or Glomusfasciculaturn, or distilled water (control), and grown for 3 months at −10 or −300 kPa soil water potential. Total porosity, air-filled porosity, water content, and mechanical resistance of the soil were determined for samples compacted to the same bulk densities and equilibrated at the same soil water potentials as were used in the greenhouse study. Root growth was reduced by the high mechanical resistance caused by bulk densities of 1.40 and 1.55 Mg • m−3 at −300 kPa water potential. At both water potentials, total length of lateral roots and fibrosity of the root system of both tree species decreased significantly when bulk density increased from 1.40 to 1.55 Mg • m−3. Air-filled porosity less than 0.12 m3 • m−3 limited root growth when water potential was −10 kPa, and mechanical resistance greater than 3438 kPa restricted growth at −300 kPa. At −10 kPa, root length and fibrosity were greatest for inoculated sweet gum seedlings at each bulk density. At −300 kPa, sweet gum seedlings inoculated with G. fasciculatum had the greatest root length and fibrosity at the low and medium bulk densities. Mycorrhizal effects on root length of yellow-poplar were variable, and fibrosity was not significantly affected by mycorrhizal treatment.

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991 REGULATION OF PLANT GROWTH RESPONSES TO LOW SOIL WATER POTENTIALS

HortScience ◽

10.21273/hortsci.29.5.571b ◽

1994 ◽

Vol 29 (5) ◽

pp. 571b-571

Author(s):

Robert E. Shar

Keyword(s):

Plant Growth ◽

Root Growth ◽

Growth Inhibition ◽

Shoot Growth ◽

Crop Improvement ◽

Plant Water ◽

Growth Responses ◽

Water Deficits ◽

Definitive Evidence ◽

Water Potentials

Plant water deficits usually result in severe inhibition of shoot growth, while root growth is less inhibited or even promoted. Recent advances in understanding the physiology of the differential responses of root and shoot growth to low water potentials will be reviewed. While it might be readily accepted that hormones arc important in transducing environmental conditions into growth responses, there is surprisingly little definitive evidence for the role of any hormone in regulating plant growth in soils of low water potential. Using maize seedlings as a model system, the increase in ABA that accompanies plant water deficits has been shown to be required for root growth maintenance, and also to play a role in shoot growth inhibition. The action of ABA in root growth maintenance appears to involve regulation of ethylene synthesis and/or sensitivity, while the mechanism of shoot growth inhibition is not known. Evidence that ABA acts as a root `signal controlling shoot growth in drying soil will also be considered. The importance of osmotic adjustment as a mechanism of growth maintenance at low water potentials has been questioned by suggestions that solute accumulation may be merely a consequence of stress-induced growth inhibition. Recent studies will be discussed which do not support this idea, and suggest that the response may be useful for crop improvement.

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