Aboveground dry matter partitioning responses of black spruce to directional-specific indices of local competition

2003 ◽  
Vol 33 (10) ◽  
pp. 1832-1845 ◽  
Author(s):  
P F Newton ◽  
P A Jolliffe

This study assessed the effects of directional-specific indices of local competition on the partitioning of aboveground dry matter of individual black spruce (Picea mariana (Mill.) BSP) trees. Historical tree reconstruction sampling techniques were used to estimate stem, branch, and foliage ovendry masses by year of formation (cohort age-class) of 125 subject trees situated within 15 density-stressed stands. Component-specific modular mass proportion calculated on an individual and cumulative cohort age-class basis was employed as an index of dry matter partitioning. Analytically, local competitors were stratified into one of four competition classes based on their relative size differential with respect to the subject tree. Sequential competition analysis was used to assess directional-specific partitioning responses to competition accumulating upwards from below and downwards from above. Furthermore, within the sequential competition analysis framework, the effects of the individual competition strata on partitioning were assessed employing stepwise multivariate analysis of variance. The results supported the presence of an asymmetric relationship dominated by competition from above in which branch partitioning was the most affected. Specifically, competition from larger-sized competitors resulted in decreased branch mass proportions whereas competition from smaller-sized competitors had no appreciable effect. These results are in accord with the hypothesis that black spruce responds to competition via an adaptive phenotypic plastic response in which branch growth declines and (or) branch abscission rates increase with increasing competition from above.

1993 ◽  
Vol 23 (9) ◽  
pp. 1917-1929 ◽  
Author(s):  
P.F. Newton ◽  
P.A. Jolliffe

Three density-stressed black spruce (Piceamariana (Mill.) B.S.P.) populations that naturally regenerated following harvesting in 1970 were selected for study within central insular Newfoundland. Employing historical tree and stand reconstruction techniques, bark, stem, branch, foliage, and total mass distributions were estimated by age-class. Regression analysis was used to assess the effect of density stress on distributional indices, and stepwise multivariate analysis of variance was used to investigate dry matter partitioning patterns. Bark and foliar mass proportions increased with increasing density stress, whereas stem and branch mass proportions declined. Among components, decreased stem proportions best expressed the effects of increasing density stress on dry matter partitioning. Asymmetry within the mass frequency distributions for bark, branch, and foliar components shifted from negative skewness at low relative densities to positive values at high relative densities. Inequality (mass concentration) within the stem mass frequency distributions remained constant, whereas inequality within the bark mass frequency distribution declined in direct proportion to increasing density stress. Inequality within both the branch and foliar mass distributions had curvilinear relationships with increasing density stress: inequality increased from low to intermediate levels of density stress, but declined thereafter. Specific leaf areas did not differ among trees of varying size, suggesting that competition for light may not have been of consequence within the sampled stands. The results are consistent with a resource depletion competitive process, implying that competition within the dense second-growth black spruce stands may have been principally for belowground resources.


1998 ◽  
Vol 28 (2) ◽  
pp. 259-275 ◽  
Author(s):  
P F Newton ◽  
P A Jolliffe

The objective of this study was to develop and subsequently apply an individual-tree analytical approach for assessing resource competition processes within monospecific, even-aged, and spatially heterogeneous black spruce (Picea mariana (Mill.) BSP) stands. The approach consisted of five basic steps: (1) ranking competitors with respect to subject tree size using a relative scale, (2) stratifying competitors into competition strata based on their relative size differential with respect to a subject tree, (3) quantifying the intensity of competition within each stratum using spatially explicit local competition indices and subsequently formulating directional-specific cumulative indices, (4) regressing relative measures of stem growth against each directional-specific index, and (5) graphically and statistically assessing differences in resultant standardized regression coefficients as competition accumulated upward from below and downward from above. This analytical framework was used with stem growth data derived from 401 subject trees situated within 18 monospecific, even-aged, density-stressed, and spatially heterogeneous black spruce stands. The results indicated directional-specific asymmetrical relationships between subject trees and their neighbours in which increasing competition from above resulted in declines in stem production. Consequently, these results were in accord with those expected when competition is dominated by a resource preemption process.


2020 ◽  
Vol 8 (5) ◽  
pp. 2667-2669
Author(s):  
Samarth Tewari ◽  
Gurvinder Singh ◽  
Avikal Kumar ◽  
Narendra Bhandari ◽  
Saurabh Gangola

2020 ◽  
Vol 207 (1) ◽  
pp. 120-127
Author(s):  
Yusuke Masuya ◽  
Etsushi Kumagai ◽  
Maya Matsunami ◽  
Hiroyuki Shimono

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amanullah ◽  
Shah Khalid ◽  
Farhan Khalil ◽  
Mohamed Soliman Elshikh ◽  
Mona S. Alwahibi ◽  
...  

AbstractThe dry matter partitioning is the product of the flow of assimilates from the source organs (leaves and stems) along the transport route to the storage organs (grains). A 2-year field experiment was conducted at the agronomy research farm of the University of Agriculture Peshawar, Pakistan during 2015–2016 (Y1) to 2016–2017 (Y2) having semiarid climate. Four summer crops, pearl millet (Pennisetum typhoidum L.), sorghum (Sorghum bicolor L.) and mungbean (Vigna radiata L.) and pigeonpea (Cajanus cajan L.) and four winter crops, wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), fababean (Vicia faba) and rapeseed (Brassica napus) were grown under two irrigation regimes (full vs. limited irrigation) with the pattern of growing each crop either alone as sole crop or in combination of two crops in each intercropping system under both winter and summer seasons. The result showed that under full irrigated condition (no water stress), all crops had higher crop growth rate (CGR), leaf dry weight (LDW), stem dry weight (SDW), and spike/head dry weight (S/H/PDW) at both anthesis and physiological maturity (PM) than limited irrigated condition (water stress). In winter crops, both wheat and barley grown as sole crop or intercropped with fababean produced maximum CGR, LDW, SDW, S/H/PDW than other intercrops. Among summer crops, sorghum intercropped either with pigeon pea or with mungbean produced maximum CGR, LDW, SDW, and S/H/PDW at both growth stages. Sole mungbean and pigeon pea or pigeon pea and mungbean intercropping had higher CGR, LDW, SDW, S/H/PDW than millet and sorghum intercropping. On the other hand, wheat and barley grown as sole crops or intercropped with fababean produced maximum CGR, LDW, SDW, and S/H/PDW than other intercrops. Fababean grown as sole crop or intercropped with wheat produced higher CGR, LDW, SDW, and S/H/PDW at PM than intercropped with barley or rapeseed. From the results it was concluded that cereal plus legume intercropping particularly wheat/fababean in winter and sorghum/pigeon pea or sorgum/mungbean in summer are the most productive intercropping systems under both low and high moisture regimes.


2012 ◽  
Vol 34 (4) ◽  
pp. 1235-1244 ◽  
Author(s):  
Layara Alexandre Bessa ◽  
Fabiano Guimarães Silva ◽  
Marialva Alvarenga Moreira ◽  
João Paulo Ribeiro Teodoro ◽  
Frederico Antônio Loureiro Soares

Knowledge of the mineral nutrition requirements of mangabeira (Hancornia speciosa Gomes) is relatively scarce and rudimentary because there is a lack of consistent data concerning its nutritional demands at different developmental stages. The aim of this research was to characterize the visual symptoms of macronutrient deficiencies and to evaluate the effects of these deficiencies on the growth, the production of dry matter, and the leaf content of mangabeira. To achieve this goal, a greenhouse experiment was conducted at the Goiano Federal Institute (Instituto Federal Goiano) in Rio Verde - GO, from January to June 2011 in which mangabeira plants were arranged in a random block design and grown in nutrient solutions. This experiment was replicated four times. The plants were treated with either a complete nutrient solution or a nutrient solution from which the individual macronutrient of interest (nitrogen (N), phosphorous (P), potassium (K), magnesium (Mg), calcium (Ca), or sulfur (S) had been omitted. The omission of a macronutrient from the nutrient solution resulted in morphological alterations that were characteristic symptoms of the particular nutritional deficiency and caused decreases in growth and dry matter mass production. The accumulation of macronutrients displayed the following order in mangabeira leaves: N>K>Ca>P>S>Mg.


2016 ◽  
Vol 44 (1) ◽  
pp. 245-249 ◽  
Author(s):  
Attila OMBÓDI ◽  
Andrea LUGASI ◽  
Hussein Gehad DAOOD ◽  
Mária BERKI ◽  
Lajos HELYES

Irrigation is a prerequisite for economical onion production under dry conditions. However, its effect on dry matter and nutrient content often remains a concern for growers. A direct sown onion hybrid was grown under open field, rain-fed and irrigated conditions for three years, investigating the effects of air temperature and water supply on some nutritive constituents. Dry matter, storage sugar, total flavonol and total polyphenol content showed strong positive correlation with average air temperature and negative correlation with water supply. However, irrigation had a positive effect on storage sugar and dry matter content. Presumably better water supply during dry periods ensured by irrigation provided the basis for higher photosynthetic production, and hereby more dry matter partitioning and accumulation in the bulb, a storage organ. An unexpected decrease in vitamin C content was experienced in 2011 and 2012, compared to the result of 2010, which was explained by the hot and dry conditions of the pre-harvest irrigation cut-off period. Fibre and ash content was found to be the most stable nutritional characteristics, affected neither by the environmental conditions, nor by the irrigation. Irrigation has proved to be very beneficial for direct sown onion, doubling bulb yield while not affecting the nutritive quality negatively.


Bragantia ◽  
2012 ◽  
Vol 71 (3) ◽  
pp. 394-399 ◽  
Author(s):  
Djeimi Isabel Janisch ◽  
Jerônimo Luiz Andriolo ◽  
Vinícius Toso ◽  
Kamila Gabriele Ferreira dos Santos ◽  
Jéssica Maronez de Souza

The objective of this research was to determine growth and dry matter partitioning among organs of strawberry stock plants under five Nitrogen concentrations in the nutrient solution and its effects on emission and growth of runner tips. The experiment was carried out under greenhouse conditions, from September 2010 to March 2011, in a soilless system with Oso Grande and Camino Real cultivars. Nitrogen concentrations of 5.12, 7.6, 10.12 (control), 12.62 and 15.12 mmol L-1 in the nutrient solution were studied in a 5x2 factorial randomised experimental design. All runner tips bearing at least one expanded leaf (patent requested) were collected weekly and counted during the growth period. The number of leaves, dry matter (DM) of leaves, crown and root, specific leaf area and leaf area index (LAI) was determined at the final harvest. Increasing N concentration in the nutrient solution from 5.12 to 15.12 mmol L-1 reduces growth of crown, roots and LAI of strawberry stock plants but did not affect emission and growth of runner tips. It was concluded that for the commercial production of plug plants the optimal nitrogen concentration in the nutrient solution should be 5.12 mmol L-1.


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