Water relations, photosynthetic capacity, and root/shoot partitioning of photosynthate as determinants of productivity in hybrid poplar

1989 ◽  
Vol 67 (6) ◽  
pp. 1689-1697 ◽  
Author(s):  
T. J. Tschaplinski ◽  
T. J. Blake
Keyword(s):  
Net Photosynthetic Rate ◽  
Biomass Production ◽  
Photosynthetic Rate ◽  
Populus Deltoides ◽  
Hybrid Poplar ◽  
Net Photosynthesis ◽  
Unit Leaf ◽  
Vigorous Growth ◽  
The Difference ◽  
Causal Sequence

Physiological determinants of productivity, including net photosynthesis, root/shoot partitioning of photosynthate, and leaf retention were investigated for three Populus deltoides Bartr. × nigra L. (DN 2, DN 22, DN 15) and two P. balsamifera L. × deltoides Bartr. (Jackii 4, Jackii 7) hybrids. Performance of the different hybrids was compared under controlled greenhouse conditions and in the field. There was a 2.4-fold difference in biomass production between the faster growing DN 2 and the slower growing DN 15 after 100 days growth in the greenhouse, and a 1.5-fold difference after the 1st year's growth in the field. When coppice regrowth of the two Jackii hybrids was compared after 143 days under field conditions, the biomass production of Jackii 4 was 2.2 times that of Jackii 7 and net photosynthetic rate per unit leaf area was 50 % higher than that of Jackii 7 over most of the summer. Many physiological and morphological factors contributed to the more vigorous growth of coppice DN 2 and Jackii 4. These included vigorous initial root growth relative to shoot growth, the ability to maintain higher xylem pressure potentials, net photosynthetic rate, and transpiration rate. These factors may have delayed leaf senescence and late-season photosynthetic decline of older leaves until later in the growing season. The possible causal sequence of physiological events contributing to the difference in productivity and the use of these factors for the early selection of productive hybrids or genotypes are discussed.

Correlation between early root production, carbohydrate metabolism, and subsequent biomass production in hybrid poplar

1989 ◽  
Vol 67 (7) ◽  
pp. 2168-2174 ◽  
Author(s):  
T. J. Tschaplinski ◽  
T. J. Blake
Keyword(s):  
Biomass Production ◽  
Root Length ◽  
Populus Deltoides ◽  
Hybrid Poplar ◽  
Dry Weight ◽  
Root Production ◽  
Stem Cuttings ◽  
Total Root Length ◽  
Growth Processes ◽  
Carbohydrate Utilization

The relationship between the rooting patterns of five poplar hybrids and stem carbohydrate dynamics was investigated to determine if the availability or metabolism of carbohydrates was limiting early root production of cuttings. Differences in early root production (i.e., number, length, and dry weight) after 17 days paralleled the subsequent differences in accumulation of aboveground biomass that were observed when two Populus balsamifera L. × deltoides Bartr. (Jackii 4 and Jackii 7) and three Populus deltoides Bartr. × nigra L. (DN 2, DN 22, and DN 15) hybrids were compared. Total root length and dry weight of Jackii 4 was four times that of Jackii 7. Both DN 2 and DN 22 had a total root length twice that of DN 15. Rooting characteristics may be useful criteria for selection of productive clones. Carbohydrate analysis of stem cuttings suggested that hybrids differing in biomass production displayed different patterns of carbohydrate utilization. The concentrations of glucose and myoinositol declined more in faster growing hybrids (Jackii 4, DN 2, DN 22) than in slower growing hybrids (Jackii 7, DN 15). The results suggest that faster growing hybrids consume monosaccharides in growth processes, whereas the slower growing hybrids convert monosaccharides into alternative storage forms and use less in growth processes. The initial myoinositol concentration in stem cuttings of poplar hybrids was correlated (r2 = 0.95) with root dry weight produced after 17 days, but the initial starch concentration was unrelated to later root biomass production. The results suggest that initial myoinositol concentration in cuttings may be used in early selection for rooting performance.

C4Photosynthesis in Smooth Pigweed

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 127-130 ◽  
Author(s):  
David T. Patterson
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Net Photosynthesis ◽  
Gas Analysis ◽  
Photosynthetic Characteristics ◽  
Optimum Temperature ◽  
Amaranthus Hybridus ◽  
Photosynthetic Rates ◽  
Compensation Concentration ◽  
Smooth Pigweed

The response of net photosynthetic rate to temperature and light, the rate of photorespiration, the compensation concentration for CO2, and the pathway of CO2fixation in smooth pigweed (Amaranthus hybridusL.) were investigated using infrared gas analysis and14CO2. Maximum net photosynthetic rates of whole shoots were 45 mg CO2dm-2hr-1at 30 C and 7.8 klux. Intact whole shoots were not light saturated at 10 klux. The optimum temperature for net photosynthesis was between 30 C and 40 C. Photorespiration was low and the CO2compensation concentration was 7 ppm. After a 5-sec exposure to14CO2in the light, label was detected in oxaloacetate, malate, and aspartate. It was concluded that smooth pigweed has the gross photosynthetic characteristics and CO2fixation pathway typical of C4or Hatch-Slack plants.

Comparative carbon dioxide exchange for two Populus clones grown in growth room, greenhouse, and field environments

1984 ◽  
Vol 14 (6) ◽  
pp. 924-932 ◽  
Author(s):  
Neil D. Nelson ◽  
Paul Ehlers
Keyword(s):  
Net Photosynthetic Rate ◽  
Leaf Area ◽  
Photosynthetic Rate ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Growth Environment ◽  
Photosynthetic Rates ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Growth Room

Light-saturated net photosynthetic rates per unit leaf area were 1.6–2.1 times greater for the photosynthetically mature leaves of plants of two hybrid Populus clones (NC-5260, 'Tristis No.1' (Populustristis Fisch. × P. balsamifera L.); NC-5326, 'eugenei' (P. deltoides Bartr. ex Marsh. × P. nigra L.)) grown in pots in the field than in comparable plants from a controlled environment growth room and a winter greenhouse. Stomatal resistances to CO2 in the field trees were only 0.4–0.6 of those in growth room and greenhouse trees. Mesophyll (residual) resistances to CO2 in field trees were 0.4–0.8 of those in growth room and greenhouse trees. Field plants had specific leaf weights 1.5–1.8 times higher than growth room and greenhouse plants, likely primarily owing to the greater average photosynthetic photon flux density in the field (835, 225, and 142 μE m−2 s−1 for field, growth room, and greenhouse conditions, respectively). When net photosynthetic rates (Ps) were corrected for the differences in specific leaf weights to derive net photosynthetic rate per unit leaf dry weight, the values were similar for plants from the three environments (Ps in field trees was 0.9–1.2 times Ps in growth room and greenhouse trees); gross photosynthetic rates per unit leaf weight were even more similar. Internal leaf CO2 concentrations, and photorespiration and dark respiration rates per unit leaf area were not related to growth environment. However, photorespiration rate as a percentage of net photosynthetic rate was lower in the field trees (12–16% in field trees, 19–24% in growth room trees, and 23–39% in greenhouse trees). Net photosynthetic rate was shown to be under strong genetic control in these clones. The effects of growth environment on variables of carbon exchange are sensitive to the basis of expression of those variables.

Evidence for nonstomatal inhibition of net photosynthesis in rapidly dehydrated shoots of Populus

1986 ◽  
Vol 16 (6) ◽  
pp. 1371-1375 ◽  
Author(s):  
G. Scarascia-Mugnozza ◽  
T. M. Hinckley ◽  
R. F. Stettler
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Net Photosynthesis ◽  
Volume Shrinkage ◽  
Sharp Reduction ◽  
Stomatal Behaviour ◽  
Net Assimilation ◽  
Protoplast Volume

Results are presented on the decline of net photosynthesis during the application of rapid water stress to excised shoots of different Populus L. clones. Six clones were selected from the species Populustrichocarpa Torr. & Gray, Populusdeltoides Bartr., and from the hybrid Populustrichocarpa × Populusdeltoides, taking into account the differences in stomatal behaviour between and within these species. The two most productive P. trichocarpa clones and the hybrid clone, characterized by a reduced ability to close stomata during leaf desiccation, showed, nevertheless, a sharp reduction of net photosynthesis at water potentials lower than −1.5 MPa. In contrast, the inhibition of net assimilation in the P. deltoides clone, caused by water stress, was accompanied by a reduction in stomatal conductance. In all studied clones the decrease in net photosynthetic rate followed closely the point of turgor loss of the leaves, indicating a possible relationship between nonstomatal inhibition of photosynthesis and protoplast volume shrinkage.

Diurnal variation in net photosynthetic rate and influencing environmentalfactors of Elaeagnus mollis Diels leaf

2009 ◽  
Vol 17 (3) ◽  
pp. 474-478
Author(s):  
Qun-Long LIU ◽  
Chan-Juan NING ◽  
Duo WANG ◽  
Guo-Liang WU ◽  
Hong-Mei ZHANG ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Elaeagnus Mollis

scholarly journals Changes in peanut canopy structure and photosynthetic characteristics induced by an arbuscular mycorrhizal fungus in a nutrient-poor environment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yinli Bi ◽  
Huili Zhou
Keyword(s):  
Net Photosynthetic Rate ◽  
Leaf Area ◽  
Photosynthetic Rate ◽  
Mycorrhizal Fungus ◽  
Canopy Structure ◽  
Arbuscular Mycorrhizal ◽  
Photosynthetic Characteristics ◽  
Total Leaf Area ◽  
Tiller Angle ◽  
Amf Inoculation

AbstractA well-developed canopy structure can increase the biomass accumulation and yield of crops. Peanut seeds were sown in a soil inoculated with an arbuscular mycorrhizal fungus (AMF) and uninoculated controls were also sown. Canopy structure was monitored using a 3-D laser scanner and photosynthetic characteristics with an LI-6400 XT photosynthesis system after 30, 45 and 70 days of growth to explore the effects of the AMF on growth, canopy structure and photosynthetic characteristics and yield. The AMF colonized the roots and AMF inoculation significantly increased the height, canopy width and total leaf area of the host plants and improved canopy structure. AMF reduced the tiller angle of the upper and middle canopy layers, increased that of the lower layer, reduced the leaf inclination of the upper, middle and lower layers, and increased the average leaf area and leaf area index after 45 days of growth, producing a well-developed and hierarchical canopy. Moreover, AMF inoculation increased the net photosynthetic rate in the upper, middle and lower layers. Plant height, canopy width, and total leaf area were positively correlated with net photosynthetic rate, and the inclination angle and tiller angle of the upper leaves were negatively correlated with net photosynthetic rate. Overall, the results demonstrate the effects of AMF inoculation on plant canopy structure and net photosynthetic rate.

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