Seed size effects and competitive ability in Thlaspi arvense L. (Brassicaceae)

Botany ◽  
2008 ◽  
Vol 86 (3) ◽  
pp. 259-267 ◽  
Author(s):  
David J. Susko ◽  
Paul B. Cavers

We examined the effects of seed size on plant size and competitive ability of Thlaspi arvense L. grown with and without intraspecific competition under contrasting soil fertility regimes. For solitary plants from each of four half-sibship families, seed mass was positively correlated with percentage germination, cotyledon size, and plant biomass after 15 d of growth, but differences in plant biomass largely disappeared at later dates. Small and large seeds of a single maternal family were sown in uniform or mixed arrangements of seed size classes (small:large; 100%:0%; 75%:25%; 50%:50%; 25%:75%; 0%:100%) at each of two densities (8 or 16 seeds·pot–1) under low and high soil nutrient regimes. In mixtures at low density under low soil fertility, plants from small seeds had significantly lower relative yields than expected. At high density, under either low or high nutrient conditions, plants from large seeds had significantly greater relative yields than expected. Hence, under most conditions, size inequalities between plants from seeds of different size resulted in a relative competitive advantage for plants from large seeds. The duration and extent of differences in plant size arising from T. arvense seeds of contrasting size depends on maternal genetic differences, intensity of intraspecific competition, and soil fertility.

Botany ◽  
2009 ◽  
Vol 87 (5) ◽  
pp. 475-481 ◽  
Author(s):  
Jacob Weiner ◽  
Lars Rosenmeier ◽  
Emma Soy Massoni ◽  
Josep Nogués Vera ◽  
Eva Hernández Plaza ◽  
...  

Several purported cases of plasticity in plant allocation patterns appear to be the effects of size and allometric growth (“apparent plasticity”). To ask whether there is true plasticity (i.e., a change in the allometric trajectory) in reproductive allocation in Senecio vulgaris  L., we grew S. vulgaris plants at high and low levels of water, nutrients, and competition, and analyzed the relationship between vegetative and seed biomass. Plant size was the major determinant of reproductive output, accounting for 83% of the variation in log (seed mass). There were also significant effects of the treatments that were not due to size, accounting for an additional 9% of the variation. The treatments affected the allometric coefficient (intercept), not the allometric exponent (slope) of the relationship, reflecting a small but significant shift in the efficiency of conversion of total plant biomass into reproductive biomass. In a second experiment, we grew S. vulgaris plants at three nutrient levels and allowed all individuals to complete their life cycles. Again, nutrient level had a small but significant effect on the allometric coefficient. Plasticity in reproductive allocation exists, but is very limited. The primary effects of the environment on the reproductive output of S. vulgaris occur via plant size.


2003 ◽  
Vol 54 (10) ◽  
pp. 969 ◽  
Author(s):  
D. K. Singh ◽  
V. Singh

In a glasshouse study, two experiments were conducted to understand how inherent variability, such as the seed size or mass, and formation of adventitious nodal roots might influence the tolerance of various wheat and triticale cultivars at different growth stages to waterlogging. Waterlogging at germination resulted in 11% seedling mortality, but the waterlogged seedlings had a 19% increase in shoot mass per plant, with no difference in root mass compared with non-waterlogged seedlings. Waterlogging at the 3-leaf stage was deleterious to only a few cultivars. On average, larger seed resulted in greater plant growth for most of the cultivars, and seed mass was positively related to the plant biomass and adventitious nodal root mass under waterlogged conditions. A decreasing oxygen concentration with increasing duration of waterlogging and soil depth did not affect the plant growth and visual stress symptoms, chlorosis, until the oxygen concentration decreased to less than 10% in the bottom depths. The highest yielding triticale cultivar, Muir, and wheat cultivars Brookton and Frame had the greatest seed mass, plant biomass, and relative growth rates under waterlogged conditions, compared with the lowest yielding wheat cultivars, Amery, Silverstar, and More. However, the degree of 'waterlogging tolerance', expressed as the percent ratio of plant biomass or growth rates under waterlogged conditions relative to the non-waterlogged control conditions, appeared to be greatest for the low-yielding cultivars, indicating a 'cautious approach' when screening tolerant cultivars.


2020 ◽  
Vol 126 (7) ◽  
pp. 1109-1128
Author(s):  
John G Hodgson ◽  
Gabriel Montserrat Marti ◽  
Bozena Šerá ◽  
Glynis Jones ◽  
Amy Bogaard ◽  
...  

Abstract Background and Aims Plants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified. For annuals, seed number should simply be a positive function of vegetative biomass and a negative function of seed size. Methods Using published values of comparative seed number as the ‘gold standard’ and a large functional database, comparative seed yield and number per plant and per m2 were predicted by multiple regression. Subsequently, ecological variation in each was explored for English and Spanish habitats, newly calculated C-S-R strategies and changed abundance in the British flora. Key Results As predicted, comparative seed mass yield per plant was consistently a positive function of plant size and competitive ability, and largely independent of seed size. Regressions estimating comparative seed number included, additionally, seed size as a negative function. Relationships differed numerically between regions, habitats and C-S-R strategies. Moreover, some species differed in life history over their geographical range. Comparative seed yield per m2 was positively correlated with FAO crop yield, and increasing British annuals produced numerous seeds. Nevertheless, predicted values must be viewed as comparative rather than absolute: they varied according to the ‘gold standard’ predictor used. Moreover, regressions estimating comparative seed yield per m2 achieved low precision. Conclusions For the first time, estimates of comparative seed yield and number for >800 annuals and their predictor equations have been produced and the ecological importance of these regenerative traits has been illustrated. ‘Regenerative trait-based ecology’ remains in its infancy, with work needed on determinate vs. indeterminate flowering (‘bet-hedging’), C-S-R methodologies, phylogeny, comparative seed yield per m2 and changing life history. Nevertheless, this has been a positive start and readers are invited to use estimates for >800 annuals, in the Supplementary data, to help advance ‘regenerative trait-based ecology’ to the next level.


2020 ◽  
Vol 36 (3) ◽  
pp. 115-122
Author(s):  
Alejandra I. Domic ◽  
José M. Capriles ◽  
Gerardo R. Camilo

AbstractIn vascular plants, larger seeds are generally associated with higher germination potential, healthier seedlings and overall higher rates of survivorship. How this relationship holds or what other physiological tradeoffs evolved in plants adapted to high-altitude environments, such as the tropical and subtropical highland Polylepis tree, remain unclear. In this study, we evaluated the relationship between seed mass and seedling performance by testing the reserve effect, the metabolic effect, and the seedling-size effect hypotheses in Polylepis tomentella Weddell (Rosaceae). Since the relationship between fitness and seed size can often depend on maternal plant size, we additionally investigated the association between germination success, seedling performance (survival, relative growth rate (RGR) and height), and size of bearing-seed trees under controlled greenhouse conditions. Our results showed that heavier seeds are more likely to germinate, but we did not find evidence that could support the reserve effect, metabolic effect or seedling-size effect. As seedlings from larger and medium seeds exhibited comparatively similar RGR, survival percentages and final size, maternal plant size was positively associated with improved seed quality and seedling performance. These results demonstrate that seed mass and maternal size during early seedling establishment are critical for Polylepis persistence, demography and conservation.


Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Abul Hashem ◽  
S. R. Radosevich ◽  
M. L. Roush

Density and spatial arrangement (rectangularity) effects on the competitive relationships, yield performance, and dynamics in canopy dominance of winter wheat and Italian ryegrass were evaluated using two addition series experiments. In experiment 1, combinations of six densities of each species formed the treatment matrix of addition series. In experiment 2, each species was tested at four densities and three rectangularities (RE) of winter wheat. In monocultures, crop density (plants per square meter) explained 82 to 85% of the total variation in the per-plant biomass of winter wheat in experiment 1. In mixtures of crop and weed, initial wheat density (N1) and initial ryegrass density (N2) and interaction of N1and N2explained 74 to 80% of the total variation in the per-plant biomass of winter wheat and 68 to 79% of Italian ryegrass in experiment 1. Intraspecific competition was apparent between 15 and 90 days after emergence (DAE) in winter wheat and between 90 and 170 DAE in Italian ryegrass. In mixtures, RE influenced plant size of Italian ryegrass up to 50 DAE only. Maximum winter wheat intraspecific competition occurred at 170 DAE, but maximum interspecific competition occurred during reproductive stages in mixtures. High RE increased seed yield, seed size, and harvest index of winter wheat and reduced biomass of Italian ryegrass. Grain yield of winter wheat was reduced up to 92% by competition from ryegrass. Even nine ryegrass plants in 100 winter wheat plants m−2reduced winter wheat grain yield by 33%. However, the extent of loss in winter wheat grain yield was less in RE 16 (wider spacing) than in RE 1 (square planting) or 4 (close row spacing). Winter wheat was the stronger competitor during vegetative stages, but Italian ryegrass became the stronger competitor during the reproductive stages of development. Winter wheat leaves dominated at the top canopy during the vegetative stage, but ryegrass dominated at the top canopy during the reproductive stages. In the top canopy of mixtures at 200 DAE, the leaf area indices (LAI) of ryegrass was 6.6 times greater than winter wheat at RE 1 compared to only 1.6 times at RE 16. Greater LAI of Italian ryegrass in the top canopy reduced photosynthetically active radiation available to winter wheat by 68% at booting stage.


2021 ◽  
Vol 13 (7) ◽  
pp. 3957
Author(s):  
Yingying Xing ◽  
Ning Wang ◽  
Xiaoli Niu ◽  
Wenting Jiang ◽  
Xiukang Wang

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI < 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 < SQI < 0.18), and class III (8.2%) was defined as poor soil fertility (SQI > 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content > soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.


2013 ◽  
Vol 726-731 ◽  
pp. 3803-3806
Author(s):  
Bing Ru Liu ◽  
Jun Long Yang

In order to revel aboveground biomass of R. soongorica shrub effect on soil moisture and nutrients spatial distribution, and explore mechanism of the changes of soil moisture and nutrients, soil moisture content, pH, soil organic carbon (SOC) and total nitrogen (TN) at three soil layers (0-10cm,10-20cm, and 20-40cm) along five plant biomass gradients of R. soongorica were investigated. The results showed that soil moisture content increased with depth under the same plant biomass, and increased with plant biomass. Soil nutrient properties were evidently influenced with plant biomass, while decreased with depth. SOC and TN were highest in the top soil layer (0-10 cm), but TN of 10-20cm layer has no significant differences (P < 0.05). Moreover, soil nutrient contents were accumulated very slowly. These suggests that the requirement to soil organic matter is not so high and could be adapted well to the desert and barren soil, and the desert plant R. soongorica could be acted as an important species to restore vegetation and ameliorate the eco-environment.


2015 ◽  
Vol 45 (6) ◽  
pp. 632-638 ◽  
Author(s):  
Kim Bannon ◽  
Sylvain Delagrange ◽  
Nicolas Bélanger ◽  
Christian Messier

Studies have reported divergent results on the effect of soil fertility and canopy opening on understory density and growth of sugar maple (AS; Acer saccharum Marsh.) and American beech (FG; Fagus grandifolia Ehrh.). The main objective of this study was to evaluate the effect of a gradient of canopy opening and soil fertility on the density and growth of AS and FG saplings in southwestern Quebec, Canada. We investigated 56 stands containing both AS and FG that were subjected to different disturbance history types (DHTs) (UF, unmanaged forest; PC, partial cut; and CC, clearcut) on various soil types. AS and FG absolute and relative sapling density varied greatly among the 56 stands; however, no significant effects of DHT, soil nutrient availability, or their interaction were found. Both species responded positively in terms of radial growth to canopy openings, with FG growth being slightly better than AS growth in PC stands compared with other canopy treatments. Contrary to our hypothesis, AS did not show significantly higher growth than FG following clear-cutting. These results do not support the idea that AS abundance and growth could be promoted by increasing the intensity of the canopy opening during harvest, at least on the generally acidic and base-poor soils that were investigated.


Author(s):  
Kasthuri Rajamani ◽  
N. Hari ◽  
M. Rajashekar

Soil fertility evaluation of an area is an important aspect in the context of sustainable agriculture production. In the present investigation KVK, Palem farm was selected in the district Nagarkurnool of Telangana and studied physico-chemical, available macro and micronutrient status using Nutrient Index approach made with the study of 60 surface soil samples and were analyzed for pH, Electrical Conductivity (EC), Organic Carbon (OC), Nitrogen (N), Phosphorus (P), Potassium (K) and micronutrients (Fe, Mn, Cu and Zn). Study results indicated that a major proportion of area soils are neutral (62.08%) and non-saline (100%). The whole study area was low in organic carbon content, ranging from 0.40 to 0.45 with a mean of 0.42%, and available nitrogen also low in the entire study area varied from 150.53 to 188.16 kg ha-1 with a mean value of 165.67 kg ha-1. The percent distribution of available P varied from medium to high status (34.48 and 72.41%), where available K was categorized under high (100%) status. With regard to micronutrients, the soils were predominantly deficient in Zn (24.13%) followed by Fe (20.68%) and Mn (6.89%).


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