Selection of flood-resistant and susceptible seedlings of Populustrichocarpa Torr. & Gray

1988 ◽  
Vol 18 (2) ◽  
pp. 271-275 ◽  
Author(s):  
Barbara A. Smit
Keyword(s):  
Leaf Area ◽  
Marked Reduction ◽  
Branch Length ◽  
Stomatal Resistance ◽  
Growth And Survival ◽  
Seed Collection ◽  
Individual Leaf ◽  
Total Branch Length ◽  
Collection Sites ◽  
Selection Of

To identify Populustrichocarpa plants with contrasting levels of resistance to flooding, seedlings from five diverse riparian sites were evaluated for growth and survival under flooding conditions. All seedlings survived 6 or 8 weeks of flooding. Total branch length and leaf number were reduced in all flooded plants relative to nonflooded controls. There was also a marked reduction in individual leaf area and increased stomatal resistance of flooded plants compared with nonflooded controls. Growth of flooded and nonflooded plants was highly variable within populations and no significant trends were found among populations. Therefore differential responses to flooding can be selected for within any of the seed collection sites. Plants that were rated as particularly resistant or susceptible fo flooding were selected for further study.

Determining the Performance of Five Ornamental Grasses under Reduced Moisture Conditions

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 491a-491
Author(s):  
James T. Cole ◽  
Janet C. Cole
Keyword(s):  
Leaf Area ◽  
Stomatal Resistance ◽  
Time Domain Reflectometry ◽  
Grass Species ◽  
Drought Period ◽  
Shoot Ratio ◽  
Relative Water ◽  
Moisture Conditions ◽  
Water Treatments ◽  
Potential Transpiration

An experiment was conducted to evaluate the performance of five ornamental grass species under reduced moisture. This experiment was conducted in the greenhouse with three water treatments for each species: 1) Well-watered plants were irrigated daily throughout the experiment, 2) acclimated-plants were exposed to four drought cycles prior to a final drought period in which measurements were taken, and 3) non-acclimated plants received daily irrigation until undergoing a drought cycle in which measurements were taken. A drought cycle was defined as the time from irrigation until Time Domain Reflectometry (TDR) measured 0 (zero). Preliminary observations determined the plants to be under severe stress, but capable of recovering at TDR measurements of 0. All plants were established from tillers of a single parent for each species. Two plants of each species for the three treatments were established in five blocks. Leaf water potential, osmotic potential, transpiration, stomatal resistance, and relative water content were measured during the drought cycle. At the end of the experiment the leaf area and root and shoot dry weights were determined, root to shoot ratio and leaf area ratio were calculated, and the plants were analyzed for macronutrient and micronutrient contents.

Distribution of epicormic branches and foliage on Douglas-fir as influenced by adjacent canopy gaps

2018 ◽  
Vol 48 (11) ◽  
pp. 1320-1330
Author(s):  
John W. Punches ◽  
Klaus J. Puettmann
Keyword(s):  
Branch Length ◽  
Canopy Gaps ◽  
Douglas Fir ◽  
Canopy Gap ◽  
Tree Age ◽  
Gap Size ◽  
Terminal Bud ◽  
Total Branch Length ◽  
A Minor ◽  
Epicormic Branches

The influence of adjacent canopy gaps on spatial distribution of epicormic branches and delayed foliage (originating from dormant buds) was investigated in 65-year-old coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco). Sample trees were selected across a broad range of local densities (adjacent canopy gap sizes) from a repeatedly thinned stand in which gaps had been created 12 years prior to our study. Lengths and stem locations of original and epicormic branches were measured within the south-facing crown quadrant, along with extents to which branches were occupied by sequential (produced in association with terminal bud elongation) and (or) delayed foliage. Epicormic branches, while prevalent throughout crowns, contributed only 10% of total branch length and 2% of total foliage mass. In contrast, delayed foliage occupied over 75% of total branch length, accounted for nearly 39% of total foliage mass, and often overlapped with sequential foliage. Canopy gap size did not influence original or epicormic branch length or location. On original branches, larger gaps may have modestly negatively influenced the relative extent of sequential foliage on branches and (or) slightly positively influenced delayed foliage mass. Delayed foliage appears to contribute substantially to Douglas-fir crown maintenance at this tree age, but canopy gap size had a minor influence, at least in the short term.

scholarly journals Selection of sowing date and biofertilization as alternatives to improve the yield and profitability of the F68 rice variety

2020 ◽  
Vol 38 (1) ◽  
pp. 61-72
Author(s):  
Yeison Mauricio Quevedo-Amaya ◽  
José Isidro Beltrán-Medina ◽  
José Álvaro Hoyos-Cartagena ◽  
John Edinson Calderón-Carvajal ◽  
Eduardo Barragán-Quijano
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Carbon Balance ◽  
Sowing Date ◽  
Dry Matter Accumulation ◽  
Phosphate Solubilizing Bacteria ◽  
Area Index ◽  
Use Of Resources ◽  
High Efficient ◽  
Selection Of

Multiple factors influence rice yield. Developing management practices that increase crop yield and an efficient use of resources are challenging to modern agriculture. Consequently, the aim of this study was to evaluate biological nitrogen fixation and bacterial phosphorous solubilization (biofertilization) practices with the selection of the sowing date. Three sowing dates (May, July and August) were evaluated when interacting with two mineral nutrition treatments using a randomized complete block design in a split-plot arrangement. Leaf carbon balance, leaf area index, interception and radiation use efficiency, harvest index, dry matter accumulation, nutritional status, and yield were quantified. Results showed that the maximum yield was obtained in the sowing date of August. Additionally, yield increased by 18.92% with the biofertilization treatment, reaching 35.18% of profitability compared to the local production practice. High yields were related to a higher carbon balance during flowering, which was 11.56% and 54.04% higher in August than in July and May, respectively, due to a lower night temperature. In addition, a high efficient use of radiation, which in August was 17.56% and 41.23% higher than in July and May, respectively, contributed to obtain higher yields and this behavior is related to the selection of the sowing date. Likewise, a rapid development of the leaf area index and an optimum foliar nitrogen concentration (>3%) were observed. This allowed for greater efficient use of radiation and is attributed to the activity of nitrogen-fixing and phosphate solubilizing bacteria that also act as plant growth promoters.

Foliage height influences specific leaf area of three conifer species

2003 ◽  
Vol 33 (1) ◽  
pp. 164-170 ◽  
Author(s):  
John D Marshall ◽  
Robert A Monserud
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Pinus Ponderosa ◽  
Specific Leaf Area ◽  
Ponderosa Pine ◽  
Branch Length ◽  
Dry Mass ◽  
Process Models ◽  
Pinus Monticola ◽  
Northern Idaho

Specific leaf area (SLA), the ratio of projected leaf area to leaf dry mass, is a critical parameter in many forest process models. SLA describes the efficiency with which the leaf captures light relative to the biomass invested in the leaf. It increases from top to bottom of a canopy, but it is unclear why. We sampled stands with low and elevated canopies (young and old stands) to determine whether SLA is related to water potential, as inferred from branch height and length, or shade, as inferred from branch position relative to the rest of the canopy, or both. We studied western white pine (Pinus monticola Dougl. ex D. Don), ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.), and interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca) in northern Idaho. SLA decreased with branch height (P < 0.0001) at rates that varied among species (P < 0.0001). Branch length had no influence on SLA (P = 0.85). We detected no differences with canopy elevation (P = 0.90), but the slopes of lines relating SLA to branch height may have differed between the canopy elevation classes (P = 0.039). The results are consistent with predictions based on the hypothesis that SLA decreases as the gravitational component of water potential falls. The lack of a strong shading effect simplifies the estimation of canopy SLA for process models, requiring only species and branch heights.

Compensatory Responses of Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti) to Partial Shading

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 541-547 ◽  
Author(s):  
Emilie E. Regnier ◽  
S. Kent Harrison
Keyword(s):  
Leaf Area ◽  
Shade Tolerance ◽  
Shoot Growth ◽  
Branch Length ◽  
Dry Weight ◽  
Xanthium Strumarium ◽  
Leaf Angle ◽  
Petiole Length ◽  
Partial Shading ◽  
Total Plant

Lower leaves of greenhouse-grown common cocklebur and velvetleaf were shaded to 5% of full light over a 12-d period while upper leaves remained exposed to full light to determine weed foliar and branching responses to partial shading similar to that encountered in soybean crops. Shading increased lower leaf senescence and specific leaf area, and decreased branch length and number of second-order leaves in both species compared to unshaded controls. Common cocklebur branched more extensively along the lower portion of its stem than velvetleaf under both shaded and unshaded conditions. Upper leaves of partially shaded velvetleaf were held in a more perpendicular position to the light source beginning 3 days after treatment (DAT) compared to upper leaves of unshaded plants. Shading of lower leaves caused an increase in upper (unshaded) leaf area beginning 3 and 6 DAT in velvetleaf and common cocklebur, respectively. Petiole length of upper leaves also increased in response to shading in both species. Total plant dry weight at 12 DAT was unaffected by shading in velvetleaf but was reduced 10% by shading in common cocklebur. While common cocklebur maintained greater lower shoot growth in the presence of shade than velvetleaf, there was a greater change in upper leaf angle by velvetleaf in response to shading than by common cocklebur. These results support previous field observations of apparent greater shade tolerance of common cocklebur compared to velvetleaf and indicate that both species have the ability to compensate for shading of lower leaves by altering upper shoot growth.

OVERWINTERING SPRUCE BUDWORM ON BLACK SPRUCE: SAMPLE-UNIT SIZE AND POPULATION DISTRIBUTION

1985 ◽  
Vol 117 (4) ◽  
pp. 395-399 ◽  
Author(s):  
Daniel J. Robison ◽  
Lawrence P. Abrahamson ◽  
Miroslaw M. Czapowskyj ◽  
Edwin H. White ◽  
Douglas C. Allen
Keyword(s):  
Population Distribution ◽  
Black Spruce ◽  
Branch Length ◽  
Spruce Budworm ◽  
Unit Size ◽  
Optimum Size ◽  
Sample Unit ◽  
Larval Distribution ◽  
Total Branch Length ◽  
Branch Distribution

AbstractOptimum size of a sample unit and within-branch distribution of overwintering spruce budworm were determined for black spruce in northern Maine. No significant differences in sample reliability were found between whole-branch and 45-cm branch-tip samples. Larval distribution on branches varied with total branch length and a model was developed to estimate the whole-branch population from a 45-cm branch tip. Use of a 45-cm branch-tip sample unit is recommended because it is biologically and statistically valid and reduces sampling costs.

The Critical Period of Weed Control in Grain Corn (Zea mays)

Weed Science ◽  
1992 ◽  
Vol 40 (3) ◽  
pp. 441-447 ◽  
Author(s):  
Michael R. Hall ◽  
Clarence J. Swanton ◽  
Glenn W. Anderson
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Weed Control ◽  
Critical Period ◽  
Field Studies ◽  
Southern Ontario ◽  
Leaf Stage ◽  
Individual Leaf ◽  
Logistic Equations ◽  
Weed Interference

Field studies were conducted in southern Ontario to determine the critical period of weed control in grain corn and the influence of weed interference on corn leaf area. The Gompertz and logistic equations were fitted to data representing increasing durations of weed control and weed interference, respectively. The beginning of the critical period varied from the 3- to 14-leaf stages of corn development However, the end of the critical period was less variable and ended on average at the 14-leaf stage. Weed interference reduced corn leaf area by reducing the expanded leaf area of each individual leaf and accelerating senescence of lower leaves. In addition, weed interference up to the 14-leaf stage of corn development impeded leaf expansion and emergence in 1989.

Defoliation frequency and the response by white clover to increasing phosphorus supply 1. Leaf dry matter yield and plant morphology responses

1997 ◽  
Vol 48 (1) ◽  
pp. 111 ◽  
Author(s):  
D. K. Singh ◽  
P. W. G. Sale
Keyword(s):  
Leaf Area ◽  
White Clover ◽  
Dry Matter ◽  
Leaf Size ◽  
Plant Morphology ◽  
Application Rate ◽  
Leaf Number ◽  
Growth And Survival ◽  
Defoliation Frequency ◽  
P Supply

A glasshouse experiment was carried out to determine how an increasing P supply influences the growth and survival of white clover plants subjected to a range of defoliation frequencies. Treatments involved the factorial combination of P application rate (0, 30, 90, and 180 mg/pot) to a P-deficient Krasnozem soil and defoliation frequency (1, 2, or 4 defoliations over 36 days). The survival of P-deficient plants was threatened by the most frequent defoliation; their leaf area declined owing to a reduction in leaf number and individual leaf size with each successive defoliation. Increasing the P supply to 180 mg/pot reversed this downward trend as the high P plants were able to maintain leaf area by increasing leaf size and number. Increasing the frequency from 1 to 4 defoliations over the 36 days also changed the form of the leaf dry matter response to added P, from an asymptotic to a linear response. The P requirement of white clover for maximum leaf yield therefore increased under frequent defoliation. This effect was also apparent for a range of morphological measurements including stolon elongation rate, leaf area, root mass, leaf number, and stolon number, where the magnitude of the P response was consistently greater for frequently defoliated plants. Exceptions included stolon mass, which responded more to P addition under infrequent defoliation.

Sign in / Sign up

Export Citation Format

Share Document