Mineral nutrient concentrations as a function of seed size within seed crops: implications for competition among seedlings and defence against herbivory

1998 ◽  
Vol 14 (2) ◽  
pp. 177-185 ◽  
Author(s):  
PETER J. GRUBB ◽  
DAVID F. R. P. BURSLEM

The intra-crop variation in the concentrations of major nutrients in the embryo-cum-endosperm (EE) fraction of seeds of 12 tree species of SE Asian lowland rain forest was investigated. Increased seed size was associated with a significant decrease in the EE concentration of N in 10 species, P and K in seven, Mg in six, and Ca in four. In contrast, the EE nutrient content increased with seed size, typically by about 1.6-fold where seed mass was 2-fold greater. In three species the allocation to protective tissues decreased with increased seed size. The results are potentially relevant to competition among young seedlings, optimal foraging by predators, allocation to defence by plants, and understanding the controls on filling of seeds.

1995 ◽  
Vol 73 (6) ◽  
pp. 817-826 ◽  
Author(s):  
D. J. Metcalfe ◽  
P. J. Grubb

Seed mass values are given for 140 species of primary lowland rain forest and associated secondary forests in Singapore. Among shade-tolerant species of primary forest there is a trend for a decrease in mean seed mass with tall trees > woody climbers > small trees > shrubs > herbs; the differences between tall trees and small trees or shrubs or herbs, and between herbs and small trees or woody climbers are significant. There are a few light-demanding herbs or shrubs in the primary forest; among small trees, light demanders have significantly lower seed mass values than shade tolerators. In 9 out of 13 comparisons within taxa including both shade tolerants and light demanders the former had appreciably larger seeds than the latter. Two out of 13 comparisons involved very small seeded shade tolerators, and one a notably large-seed light demander. Many shade-tolerant herbs, shrubs, and trees have seed mass values much smaller than those of trees of secondary forest conventionally regarded as small seeded, and exploit moist, litter-free sites, e.g., steep microslopes. The trees of secondary forests on degraded soils do not differ significantly in seed mass from those on nondegraded soils. Key words: seed mass, light requirement, regeneration, tropical rain forest, phylogenetic analysis.


Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1987
Author(s):  
Tongyin Li ◽  
Guihong Bi ◽  
Xiaojie Zhao ◽  
Richard L. Harkess ◽  
Carolyn Scagel

Mineral nutrient uptake of Hydrangea macrophylla ‘Merritt’s Supreme’ affected by nitrogen (N) fertilization rate, container type, and irrigation frequency was investigated. Rooted liners of hydrangea plants were fertilized twice weekly with a N-free fertilizer plus five N rates including 0, 5, 10, 15, or 20 mM N from ammonium nitrate (NH4NO3), irrigated once or twice daily with the same total irrigation volume, and grown in two types of one-gallon containers: a black plastic container and a biodegradable container (biocontainer), made from recycled paper. Concentrations of calcium (Ca) and magnesium (Mg) averaged in the entire plant, and iron (Fe) and manganese (Mn) in roots had increasing trends with increasing N rate. By comparison, increasing N rate had a dilution effect on root phosphorus (P), stem and root potassium (K), stem Ca and Mg, and leaf boron (B) concentrations. In general, nutrient content of each tested element increased with increasing N rate in each structure, or total in the plant. When there was a significant container type effect, plastic containers consistently had increased nutrient concentrations and content compared to biocontainers. One irrigation per day was beneficial in increasing nutrient concentrations of P, Ca, and zinc (Zn) in different plant structures.


1997 ◽  
Vol 7 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Peter J. Grubb ◽  
David A. Coomes

AbstractMean seed dry mass values were determined for 27 species of trees and shrubs in Amazonian caatinga (a forest-type especially short of nitrogen) and for 11 species in adjacent much taller forest on less poor soil. The tall trees (> 15 m) of caatinga have smaller seeds than the tall trees in adjacent forest on less infertile soil (both overall and in six taxonomically controlled comparisons), and than the tall trees in lowland rainforests elsewhere. The smaller seed size is interpreted in terms of a major advantage of keeping up seed number outweighing the marginal advantages of larger seed size. For trees of caatinga and adjacent forest considered together, there is a significantly greater concentration of P and Mg, and almost significantly greater concentration of N, in the embryo-cum-endosperm fraction of smaller-seeded species, but the content per seed of N, P and Mg is smaller in smaller seeds. The mean contribution of the seed coat (including endocarp for pyrenes) was 17% for dry mass, 3% for content of P, 10% for N and Mg, 15% for K, and 30% for Ca.


2008 ◽  
Vol 26 (2) ◽  
pp. 80-86
Author(s):  
Daniel S. Norden ◽  
Stuart L. Warren ◽  
Frank A. Blazich ◽  
David L. Nash

Abstract Seeds of southern seaoats (Uniola paniculata L.) were removed from storage in July 2004, surface disinfested with 2.6% sodium hypochlorite (NaOCl) for 15 min, and sown in styrofoam tobacco (Nicotiana tabacum L.) float trays (flats) filled with a vermiculite-based hydroponic substrate. Trays were floated in plastic tubs (one tray per tub) containing a complete nutrient solution with nitrogen (N) at 10, 60, 120, 180, or 240 mg·L−1 (ppm) from a 2N–3.5P–1K ratio (8N–32P2O5–5K2O) liquid slow-release fertilizer. After 10 weeks the study was terminated and data recorded. Total plant, top, leaf, stem, and root dry weights increased quadratically with increasing nitrogen application rate (NAR) with maximum dry weights calculated to occur with N at 140 to 150 mg-L−1, respectively. Other growth indexes of leaf area, root length, root area, plant height, crown growth index, tiller number, and leaf number also increased quadratically with increasing NAR similar to dry weight data. Leaf area, root length, and root area were maximized with N at 157, 140, and 140 mg-L−1, respectively. Root to top ratio and specific leaf area were both unaffected by NAR. Leaf mineral nutrient concentrations of N and phosphorus responded quadratically with increasing NAR whereas, foliar mineral nutrient concentrations of potassium, calcium, sulfur, sodium (Na), manganese, zinc, and copper responded linearly to increasing NARs. With the exception of Na and iron, foliar nutrient content for all analyzed nutrients increased quadratically with increasing NAR. Calculated leaf N concentration at maximum top dry weight was 31 mg·g−1. Southern seaoats can be grown successfully using the float system with optimum N rates of 140 to 150 mg·L−1 provided by a fertilizer having a 2N–3.5P–1K ratio.


1995 ◽  
Vol 120 (6) ◽  
pp. 977-982 ◽  
Author(s):  
Mack Thetford ◽  
Stuart L. Warren ◽  
Frank A. Blazich

Uniconazole was applied as a foliar spray at 0, 90, 130, 170, or 210 mg·liter-1 to rooted stem cuttings of `Spectabilis' forsythia (Forsythia ×intermedia Zab.) potted in calcined clay. Plants were harvested 0, 40, 80, 120, and 369 days after treatment (DAT). Treatment with uniconazole at 90 to 210 mg·liter suppressed leaf area and dry weight an average of 16% and 18%, respectively, compared to the nontreated controls when averaged over all harvest periods. Stem and root dry weight suppression was greatest at 80 DAT, 47% and 37%, respectively. Uniconazole suppressed root length from 15% to 36% and root area from 15% to 33% depending on harvest date. Internode length and stem diameter of uniconazole-treated plants were suppressed at all harvests except 369 DAT. Uniconazole resulted in increased and decreased root: shoot ratios 40 and 80 DAT, respectively; while root: shoot ratios were not affected for the remainder of the study. Relative growth rates of leaves, stems, and roots decreased with increasing uniconazole concentration; however, no relative growth rates were suppressed beyond 80 DAT. Generally, mineral nutrient concentrations increased as a result of uniconazole application. The proportion of mineral nutrients allocated to leaves and roots was not affected while the proportion of nutrients allocated to stems decreased with uniconazole application compared to the controls. Chemical name used: (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole).


2000 ◽  
Vol 16 (6) ◽  
pp. 853-863 ◽  
Author(s):  
NIGEL C. SIZER ◽  
EDMUND V. J. TANNER ◽  
ISOLDE D. KOSSMANN FERRAZ

Forest edges bordering on pasture were created by cutting and burning the surrounding Amazonian lowland rain forest in the dry season (June) of 1990. Litterfall was measured for 3.5 y along transects 10, 50, 100 and 250-m into the forest from the forest edge. Litterfall along the 10-m transects increased by up to 2.5 times that on spatial controls (250-m transects) in the dry season in which the edge was created. In the second dry season after edge creation litterfall at 10-m was lower than on controls, after which it returned to control rates in the second wet season, 1.5 y after edge creation. Litterfall 50-m into the forest was less affected; there was a smaller rise in the dry season in which the edge was cut, and no significant effects after that. At 100-m there was no effect of edge creation on litterfall. Phosphorus concentrations in litterfall were elevated along 10-m transects, 10–12 wk after edge creation, possibly because of reduced retranslocation prior to abscission. The changes in litterfall described here are inextricably linked to the biomass collapse, which occurs near forest-fragment edges in the same area.


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