Crop Science Grow Your Career with CSSA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (23)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Xu, Q.
Right arrow Articles by Huang, B.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Xu, Q.
Right arrow Articles by Huang, B.
Agricola
Right arrow Articles by Xu, Q.
Right arrow Articles by Huang, B.
Related Collections
Right arrow Turfgrass Management
Right arrow Temperature Stress
Right arrow Turfgrass
Crop Science 41:127-133 (2001)
© 2001 Crop Science Society of America

TURFGRASS SCIENCE

Morphological and Physiological Characteristics Associated with Heat Tolerance in Creeping Bentgrass

Qingzhang Xu and Bingru Huang

Dep. of Horticulture, Forestry, and Recreation Resources, Kansas State Univ., Manhattan, KS 66506-5506

Corresponding author (bhuang{at}oz.oznet.ksu.edu)


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Growth of creeping bentgrass (Agrostis palustris Huds.) is limited by heat stress during summer. Understanding the morphological and physiological characteristics associated with heat tolerance of creeping bentgrass would facilitate breeding programs in improving those characteristics. The objectives of this experiment were to study responses of single-leaf photosynthetic capacity, tillering, and root growth to heat stress for two creeping bentgrass cultivars differing in performance under heat stress and to determine the relative importance of these factors in heat tolerance. The cultivars L-93 (heat tolerant) and Penncross (heat sensitive) were exposed to day/night temperatures of 20/15°C (control) and 35/30°C (heat stress) in growth chambers. Canopy net photosynthetic rate (Pn), single-leaf Pn, and RuBP carboxylase (Rubisco) activity were reduced by heat stress for both cultivars. Canopy Pn of L-93 was significantly higher (more than double at 64 d of treatment) than that of Penncross under heat stress. Cultivars were not different in single-leaf Pn and Rubisco activity under either control or heat stress conditions. High temperature reduced plant density, tiller density, root number, and root fresh weight for both cultivars. L-93 had higher plant and tiller densities, greater root to tiller ratio, and more and finer roots than Penncross under control and high temperature conditions. The better performance of L-93 under heat stress was due largely to its morphological characteristics, including tillering and root growth, but was not related to single-leaf photosynthetic capacity. Narrow leaves, small plants, dense tillers, big root system, and high root-to-shoot ratio could be used to select heat tolerant cultivars.

Abbreviations: Pn, net photosynthetic rate • Rubisco, RuBP carboxylase • R/T, root-to-tiller number ratio • SRL, specific root length


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
HEAT STRESS is a major factor limiting growth of cool-season grasses in the transitional and warm climatic regions. Turf quality of creeping bentgrass, a cool-season grass frequently used on golf greens, often declines during summer when temperatures exceed its optimum (Carrow, 1996; Engelke, 1998). The extent of summer quality decline or heat tolerance of creeping bentgrass varies with cultivars and could involve changes in various morphological and physiological factors (Wu and Huff, 1983; Beard, 1999; Huang and Gao, 2000; Xu and Huang, 2000b).

A decrease in tiller density could be a major factor contributing to turf quality decline because density is one of the three components in quality evaluation (Beard, 1999; Turgeon, 1999). Declines in tiller density with increasing temperatures have been found in various cool-season grass species (Thomas and Norris, 1977; Youngner and Nudge, 1976; Youngner et al., 1978; Davies and Thomas, 1983). Lower tiller density results in reduced leaf area available for photosynthesis and, thus, can lead to decreases in canopy photosynthetic rate (Auda et al., 1966). Canopy photosynthetic rate can be affected by both leaf areas associated with plant or tiller density, leaf orientation/arrangement, and single-leaf photosynthetic capacity. Reduced canopy photosynthetic rate and carbohydrate reserves contribute to turf quality decline in creeping bentgrass under heat stress (Huang et al., 1998; Liu and Huang, 2000b). Our previous studies found that heat tolerant L-93 maintains higher canopy photosynthetic rate and carbohydrate accumulation than heat sensitive Penncross (Liu and Huang, 2000b; Xu and Huang, 2000b). Wu and Huff (1983) demonstrated that heat tolerant creeping bentgrass clones had a higher root-to-shoot ratio and smaller leaf area and thinner stolons compared with heat sensitive clones. Root growth also is positively associated with the performance of creeping bentgrass during summer because an extensive root system facilitates water uptake, increase transpirational cooling, and therefore affects heat tolerance (Beard and Daniel, 1966; Engelke, 1985; Kolb and Robberecht, 1996).

Recent studies have found that new bentgrass cultivars such as L-93 perform better in heat stress than old ones such as Penncross (Toubakaris and McCarty, 2000; Xu and Huang, 2000a,b). Leslie (1994) proposed that newly developed creeping bentgrass cultivars would be expected to be more resistant to heat stress because their canopies were finer, darker, and denser than those of old cultivars. However, major morphological and physiological characteristics associated with better heat tolerance of newly developed creeping bentgrass cultivars have not been identified. Understanding the relative involvement of various morphological and physiological characteristics in heat tolerance of creeping bentgrass would help to identify traits of heat tolerance and facilitate breeding programs in developing heat-tolerant cultivars.

Therefore, this experiment was designed to (i) examine responses of several major physiological and morphological characteristics to heat stress; and (ii) determine the relative importance of single-leaf and canopy photosynthesis capacity, and tillering and root growth characteristics in heat tolerance for two creeping bentgrass cultivars, L-93 and Penncross, differing in heat tolerance (Huang and Liu, 1999; Huang and Gao, 2000; Liu and Huang, 2000a,b; Toubakaris and McCarty, 2000; Xu and Huang, 2000a,b).


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Sod pieces of L-93 and Penncross were collected from the same aged USGA-specification putting green plots with the same cultureal conditions and transplanted into a mixture of sand and fritted clay (Profile, AILMOR, Deerfield, IL) (9:1, v/v) in clear polyethylene bags (5 cm in diameter and 40 cm in length, with eight holes pierced at the bottom for drainage). The polyethylene bags were placed in opaque polyvinylchloride tubes of the same diameter and length to prevent light exposure of roots. The tubes were placed vertically in wooden frames. Plants were grown in growth chambers at 20/15°C (day/night), photosynthetically active radiation of 400 mol m-2 s-1 at the canopy level, and a 14-h photoperiod for 60 d before temperature treatments were imposed.

Plants were exposed to two day/night temperature regimes: 20/15°C (control) and 35/30°C (heat stress) for 64 d. These test temperatures were chosen because 15 to 20°C is within the optimum temperature range for shoot and root growth of cool-season grasses, and 30 to 35°C commonly occurs in the transitional and warm climatic regions during mid-summer. During temperature treatments, grass was mowed daily at 3- to 4-mm height with an electric hair clipper, fertilized weekly with 100 mL of full-strength Hoagland's nutrient solution (Hoagland and Arnon, 1950), and watered daily until water drained freely from the bottom of the tubes to maintain adequate soil moisture (20%, v/v).

Temperatures and cultivars were arranged in a split-plot randomized design with temperature as the main plot and cultivar as the subplot and with repeated measurements to study time response to each treatment (Snedecor and Cochran, 1992). Each temperature treatment was repeated in four growth chambers. Cultivars were arranged randomly in each temperature regime in each chamber. All measurements were taken on four replicates sampled randomly in each treatment at various times. Effects of temperature, cultivar, time of treatment, and their interactions were determined by analysis of variance according to the general linear model procedure of Statistical Analysis System (SAS Institute, Cary, NC). Differences between treatments and cultivars were determined by the least significance difference (LSD) test at the 0.05 probability level, unless otherwise noted.

Turf quality was visually rated weekly after treatments were initiated on the basis of on color, density, and uniformity on a scale of 0 (worst, plants dead and brown) to 9 (best, plants healthy and green). Grasses rated at 6 or above were considered to have acceptable quality.

Canopy net photosynthetic rate (Pn) was determined biweekly from 1000 to 1400 h with LI-6400 portable photosynthesis system (LI-COR Inc., Lincoln, NE). Turf canopy was enclosed in a transparent plexiglass chamber fitted to the CO2 analyzer in LI-6400. Canopy Pn was expressed as µmol CO2 per unit turf canopy area (m2) per unit time (s). Single-leaf Pn was measured from 1000 to 1400 h biweekly with the LI-6400 portable photosynthesis system with modification of the leaf chamber. Specifically, a piece of nylon screen was put just beneath the gasket on the lower half of the leaf chamber to hold leaf pieces in place. Thirty to 50 leaf pieces (3–4 mm long) were cut from the plant and immediately laid flat onto the screen in the LI-6400 leaf chamber facing the light source. Then, another sheet of screen was put on the top of leaves in the lower gasket. The CO2 uptake of leaf pieces was measured within 30 s of excision from plants. Photo flux density of the leaf chamber was 1000 µmol m-2 s-1 provided by LI-CORs LED light source installed in the chamber. Temperature was 35 and 20°C for 35/30°C and 20/15°C treatments, respectively. CO2 concentration and relative humidity were 460 g L-1 and 60%, respectively. Leaf area was measured immediately after Pn measurement with an image analyzer (Decagon Devices, Inc. Pullman, WA). Single-leaf net photosynthetic rate was expressed as µmol CO2 per unit leaf area (m2) per unit time (s).

The activity of RuBP carboxylase (Rubisco) in leaves was determined by the method of Laurie and Steward (1993). Leaf tissue (0.5–1 g) was ground in a mortar with 10 mL cool (0–4°C) buffer solution containing 100 mM Tris-HCl (pH 7.8), 10 mM MgCl2, 1 mM EDTA, 10 mM 2-mercaptoethanol, and 12.5% (v/v) glycerol and then centrifuged at 39 000 g for 30 min. The supernatants were decanted into test tubes that were stored in ice prior to assay. Rubisco activity was measured following the incorporation of 14C into acid-stable product using NaH14CO3. A 0.5 mL of 200 mM HEPES solution containing 20 mM MgCl2, 0.2 mM Na2EDTA, and 0.2 mL of 200 mM NaH14CO3 (5 µci mL-1), and 0.1 mL supernatant were mixed in liquid scintillation vials. The vials were sealed and incubated at 25°C for 10 min. The reaction was started by adding 0.2 mL of 3 mM ribulose bis-phosphate (RuBP) solution to all vials. The vials were sealed and incubated at 25°C for 5 min with continuous shaking. The reaction was stopped by adding 0.2 mL of 2 M HCl to each vial, and all vials were left open in a hood for 12 h. Then 4 mL of scintillation cocktail was added to each vial. Radioactivity of the solution was measured with a scintillation counter (R.J. Harvey Instrument Corp., Hillsdale, NJ) and used to calculate Rubisco activity expressed as 14C activity per unit weight of protein in leaves.

Plant density (plants per unit ground area) was determined by counting the number of plants in each tube. Thirty to 40 plants were selected randomly from each tube to estimate tiller density as the number of tillers per unit ground area. Plants from four tubes in each treatment were harvested biweekly to determine root fresh weight, number, and length. Fresh weight and length of all roots in each tube were determined after roots were washed free of soil and blotted dry using paper towels. Root length was measured with an image analyzer. Specific length of all roots (alive and dead) was estimated as root length per unit fresh weight. The number of crown roots in each tube was counted. The ratio of root number to tiller number (R/T) was calculated from the number of roots and tillers in each tube.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Turf Quality
Turf quality under heat stress (35/30°C treatment) started to decline to below the control level (20/15°C treatment) at 14 d of treatment for both cultivars and decreased to below the acceptable level (6) at 28 d for Penncross and at 42 d for L-93 (Fig. 1) . Beginning at 0 d of treatment, L-93 had significantly higher quality than Penncross under control or heat stress conditions; however, Penncross had a darker green color than L-93 at 0 d. The difference in turf quality between two cultivars was significant at 0.01 probability level at 28, 54, and 65 d of heat stress, while the difference was significant at 0.05 probability level under control conditions.



View larger version (19K):
[in this window]
[in a new window]
  		Fig. 1. The responses of turf quality for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
Photosynthetic Rate and Rubisco Activity
The canopy and single-leaf Pn of both cultivars decreased dramatically when plants were first exposed to heat stress and then deceased slowly after 14 d of treatment (Fig. 2, 3) . The canopy Pn of L-93 was higher than that of Penncross at 35/30°C, while the canopy Pn between L-93 and Penncross was not different at 20/15°C. No significant difference on single-leaf Pn was found between two cultivars under both 20/15 and 35/30°C conditions.



View larger version (20K):
[in this window]
[in a new window]
  		Fig. 2. The responses of canopy photosynthetic rate (Pn) for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 


View larger version (22K):
[in this window]
[in a new window]
  		Fig. 3. The responses of single-leaf photosynthetic rate (Pn) for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
The response of Rubisco activity to heat stress was similar to that of Pn for both cultivars (Fig. 4) . Rubisco activity decreased rapidly when plants were exposed to high temperature until 9 d of treatment and then decreased slowly. Cultivars were not different in Rubisco activity under control or heat stress conditions. The decline of canopy Pn, single-leaf Pn, and Rubisco activity were more dramatically than turf quality after plants were exposed to heat stress for both cultivars (Fig. 1).



View larger version (19K):
[in this window]
[in a new window]
  		Fig. 4. The responses of RuBP carboxylase (Rubisco) activity for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
Shoot Growth
Heat stress reduced plant density, beginning at 14 d of treatment for Penncross and 28 d for L-93 (Fig. 5) . L-93 had higher plant density than Penncross under both high temperature regimes.



View larger version (23K):
[in this window]
[in a new window]
  		Fig. 5. The responses of plant density for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
Tiller density showed the same pattern as plant density in response to heat stress for both cultivars (Fig. 6) . L-93 had higher tiller density than Penncross under both temperature regimes.



View larger version (20K):
[in this window]
[in a new window]
  		Fig. 6. The responses of tiller density for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
Root Growth
The number of roots in both cultivars was reduced by high temperature to below the control level, beginning at 9 d of treatment (Fig. 7) . L-93 had more roots than Penncross under either control or heat stress conditions, particularly during heat stress.



View larger version (22K):
[in this window]
[in a new window]
  		Fig. 7. The responses of root number for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
High temperature reduced fresh weight of roots in all soil depths for both cultivars (Fig. 8) . The inhibitory effects of heat stress on root growth diminished with soil depth. The reduction in root fresh weight occurred at 3 d of heat stress for both cultivars. L-93 maintained higher root fresh weight than Penncross at all soil depths, particularly in the upper 12 cm of soil, under either temperature regime during most of the experimental period.



View larger version (22K):
[in this window]
[in a new window]
  		Fig. 8. The responses of root fresh weight for L-93 and Penncross at different soil depths to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
Specific root length (SRL) of heat-stressed plants was greater than that of the control plants after 10 d for Penncross and 40 d for L-93 (Fig. 9) . L-93 had greater SRL than Penncross for 40 d of treatment.



View larger version (20K):
[in this window]
[in a new window]
  		Fig. 9. The responses of specific root length for L-93 and Penncross to high temperatures. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 
Root to Tiller Ratio
Heat stress increased the R/T ratio for L-93, beginning at 20 d but had no effect on R/T of Penncross (Fig. 10) . L-93 had a higher R/T ratio than Penncross under either control or high temperature treatment.



View larger version (19K):
[in this window]
[in a new window]
  		Fig. 10. The responses of root to tiller number ratio (R/T) for L-93 and Penncross to high temperature. Vertical bars indicate LSDs (P = 0.05) for treatment and cultivar comparisons at a given day of treatment

 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Canopy Pn, single-leaf Pn, and Rubisco activity decreased immediately to a level significantly below the control level when Penncross and L-93 were exposed to high temperature. This indicated that photosynthesis of creeping bentgrass is sensitive to high temperature, as found in other species (Berry and Bjorkman, 1980; Harding et al., 1990; Havaux et al., 1991; Bose and Ghosh, 1995; Pastenes and Horton, 1996; Schwarz et al., 1997; Vu et al., 1997; Ranney and Ruter, 1998). The earlier and greater reduction in single-leaf Pn and Rubisco activity than in turf quality, root number, root fresh weight, tiller density, and plant density suggest that single-leaf photosynthetic capacity was more responsive to heat stress than shoot and root morphological parameters. Reductions in single-leaf Pn generally are considered to be the result of reduced availability of CO2 because of stomatal closure or nonstomatal factors, such as decreased activity of carboxylase enzymes (Kaiser, 1987). Inhibition of Rubisco activity is one reason of the reduction in single-leaf Pn during heat stress (Ku and Edwards, 1977; Myers et al., 1999). Reduced photosynthesis in creeping bentgrass limits carbohydrate accumulation in shoots and supply for root growth under heat stress (Liu and Huang, 2000b; Xu and Huang, 2000b).

Single-leaf Pn and Rubisco activity were not different between heat-tolerant L-93 and heat-sensitive Penncross. Karnok and Kneebone (1975) also detected no significant difference in single-leaf Pn between heat-tolerant and heat-susceptible cultivars of creeping bentgrass at 40°C. In contrast, cultivars of Kentucky bluegrass that were best adapted to high temperature conditions had the highest single-leaf Pn (Taylor, 1973); however, in our study, L-93 had significantly higher tiller density, more roots, and higher root to tiller ratio than Penncross. Therefore, the difference in heat tolerance between the two cultivars of creeping bentgrass was related mainly to their differences in growth characteristics including tillering and rooting rather than to single-leaf photosynthetic capacity. The higher tiller density of L-93 could contribute to its higher canopy photosynthetic rate by providing more leaves available for light interception and, thus, could enhance carbohydrate accumulation (Auda et al., 1966; Liu and Huang, 2000b; Xu and Huang, 2000a, b).

Root fresh weight and specific root length of L-93 were higher than those of Penncross, indicating that L-93 had greater volume and surface areas of roots in contact with the soil, which could facilitate water and nutrient uptakes under heat stress. An extensive root system would facilitate increase transpirational cooling and, therefore, affect heat tolerance (Beard and Daniel, 1966; Engelke, 1985; Kolb and Robberecht, 1996; Xu and Huang, 2000a). Engelke (1985) reported that creeping bentgrass cultivars that produce more roots and deeper roots were better able to survive intensive heat because they could use more of the soil moisture reservoir for transpirational cooling. Bonos and Murphy (1999) found that heat-tolerant cultivars of Kentucky bluegrass had 19% more roots at the 15- to 30-cm depth and 65% more roots at the 30- to 40-cm depth than intolerant cultivars; the extensive root system of the tolerant cultivars resulted in lower stomatal resistance and a cooler canopy. Any effects on root growth would be important for grass survival during hot summer (Schmidt, 1991; Engelke, 1998; Yelverton, 1998). Our results, combined with those of others, suggest that an extensive root system could be selected for breeding heat tolerant cultivars.

L-93 also had more tillers with narrower leaves (0.97 ± 0.09 mm, mean ± standard error) than Penncross (1.42 ± 0.12 mm). Narrow leaves and dense tillers and plants in the L-93 canopy also facilitate transpirational cooling under heat stress when soil moisture and root growth are not limiting water supply (Kolb and Robberecht, 1996; Schwarz et al., 1997). Leslie (1994) proposed that newly developed creeping bentgrass cultivars would be expected to be more resistant to heat stress because their canopies were finer, darker green, and denser, which contributes positively to light absorption and thus, photosynthetic capacity. Beard (1999) also reported that shoot density, canopy biomass, leaf blade width, and root biomass were related to heat stress tolerance.

High root-to-shoot ratio is an important mechanism in plant adaptation to environmental stresses (King et al., 1995). Higher root-to-shoot biomass ratio in heat-tolerant than in heat-sensitive cultivars has been reported in various species, including Kentucky bluegrass (Bonos et al., 1995); potato (Solanum tuberosum) (Basu and Minhas, 1991); and wheat (Triticum aestivum) (Mann et al., 1994). In our study, L-93 was found to have a higher root-to-tiller number ratio than Penncross, suggesting that L-93 had more roots to provide water, nutrients, and hormones such as cytokinins to support each individual tiller. Our results, combined with others, strongly suggested that maintaining a large root system relative to shoots would help plants survive heat stress.

In summary, high temperature reduced single-leaf and canopy photosynthetic rate, Rubisco activity, tiller density, root number, and root fresh weight for both cultivars. The higher canopy photosynthesis for L-93 than Penncross but lack of differences in single-leaf Pn and Rubisco activity between cultivars suggest that the better heat tolerance of L-93 may be related to its finer and denser turf canopy, more tillers with narrower leaves, more extensive and finer root system, and higher root to tiller ratio than its single-leaf photosynthesis capacity. Those morphological characteristics, including narrow leaves, small and dense tillers, fine and extensive root system, and high root-to-shoot ratio could be used to select for heat tolerant cultivars of creeping bentgrass.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 




This article has been cited by other articles:


Home page
 Crop Sci.Home page
J. C. Inguagiato, J. A. Murphy, and B. B. Clarke
Anthracnose Severity on Annual Bluegrass Influenced by Nitrogen Fertilization, Growth Regulators, and Verticutting
Crop Sci., July 1, 2008; 48(4): 1595 - 1607.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
X. Zhang and E. H. Ervin
Cytokinin-Containing Seaweed and Humic Acid Extracts Associated with Creeping Bentgrass Leaf Cytokinins and Drought Resistance
Crop Sci., September 1, 2004; 44(5): 1737 - 1745.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
G. V. Vergara and S. S. Bughrara
Genetic Differentiation of Tetraploid Creeping Bentgrass and Hexaploid Redtop Bentgrass Genotypes by AFLP and their Use in Turfgrass Breeding
Crop Sci., May 1, 2004; 44(3): 884 - 890.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
E. A. Guertal
Boron Fertilization of Bentgrass
Crop Sci., January 1, 2004; 44(1): 204 - 208.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
Z. Wang, Q. Xu, and B. Huang
Endogenous Cytokinin Levels and Growth Responses to Extended Photoperiods for Creeping Bentgrass under Heat Stress
Crop Sci., January 1, 2004; 44(1): 209 - 213.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
Q. Xu and B. Huang
Seasonal Changes in Carbohydrate Accumulation for Two Creeping Bentgrass Cultivars
Crop Sci., January 1, 2003; 43(1): 266 - 271.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
Q. Xu and B. Huang
Lowering Soil Temperatures Improves Creeping Bentgrass Growth under Heat Stress
Crop Sci., November 1, 2001; 41(6): 1878 - 1883.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (23)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Xu, Q.
Right arrow Articles by Huang, B.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Xu, Q.
Right arrow Articles by Huang, B.
Agricola
Right arrow Articles by Xu, Q.
Right arrow Articles by Huang, B.
Related Collections
Right arrow Turfgrass Management
Right arrow Temperature Stress
Right arrow Turfgrass

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
The SCI Journals Agronomy Journal Vadose Zone Journal
Journal of Natural Resources
and Life Sciences Education		 Soil Science Society of America Journal
Journal of Plant Registrations Journal of
Environmental Quality		 The Plant Genome