Seed size

Twenty nine germplasm lines of Chenopodium quinoa and two of Chenopodium berlandieri subsp. nuttalliae were evaluated for 12 morphological and 7 quality traits for two test seasons. The 19 traits were analyzed for cluster and principal component analysis. The first four PCs contributed 78.70 % of the variability among the germplasm lines. The first PC accounted for 39.5% of the variation and had inflorescence/plant, plant height and stem diameter as the traits with largest coefficients, all with positive sign. The characters with greatest positive weight on PC2 were days to maturity (0.309), inflorescence length (0.260) and branches/plant. All the germplasm lines were grouped into six clusters based on average linkage method. Cluster III had high values for seed yield and most of the quality traits but showed a small seed size. The dendrogram separated the two lines of C. berlandieri subsp. nuttalliae from the quinoa lines.

A field study was carried out with the potato (Solanum tuberosum L.) variety BP1 to determine the influence of plant population density and seed tuber size on the crop’s physiological growth components and yield performance under optimal field conditions. Two factors considered were seed tuber size and population density. The first factor involved four seed sizes; S1 (small), 200-350 mm in diameter; S2 (medium), 350-450 mm in diameter; S3 (large), 450-550 mm in diameter and S4 (very large), greater than 550 mm in diameter. The second factor was population density (E) and it was at three levels; level 1 (E1) at 90 by 15 cm, level 2 (E2) at 90 by 30 cm, level 3 (E3) at 90 by 45 cm spacing. Parameters measured included shoot emergence (germination), haulm growth and yield. There were significant differences in mean percentage germination at 9, 10, 11 and 12 days after planting across the four seed sizes. Plants from larger seed potato tubers exhibited greater
physiological growth and yield (kg/ha) compared to smaller seed tubers when the experiment was terminated at 95 days after
emergence. Large and very large seed potato tubers exhibited greater overall resource use efficiency of allocation of metabolites as measured by growth components and yield at all plant density levels compared to small and medium sized seed tubers. This had implications on the duration of the bulking, physiological growth and consequently on yields obtained at harvest. At the same time, plant population density had no significant (p>0.05) effect on the number of days to emergence. From the results obtained in this study, it can be concluded that the optimum plant population density for good yield was 90 by 30 cm and that large and very large seed sets gave the best yield. © 2012 Friends Science Publishers

Better understanding of the functional biology of early angiosperms may clarify eco- logical factors surrounding their origin and early radiation. Phylogenetic studies identify Ambor- ella, Nymphaeales (water lilies), Austrobaileyales, and Chloranthaceae as extant lineages that branched before the radiation of core angiosperms. Among living plants, these lineages may rep- resent the best models for the ecology and physiology of early

The ornamentation (trichomes, lithocysts and stomata) of Peristrophe paniculata (Forssk.) Brummitt. seedling is described. Seedling appeared to be " Phanerocotylar-epigeal-foliaceous type ". P. paniculata appeared to consist of lithocysts in all seedling components. Generally, they were of varied shapes and sizes. They are much longer than wider. Each lithocyst contained numerous cystoliths. The lithocyst density on cotyledonary and foliar surfaces was almost comparable-averaging around 13 to 15 lithocysts per mm 2. On cotyledon, lithocysts were predominantly of RR (Both ends round) type. RN (One end obtuse other tapering) or NN (both ends tapering) types were absent from ventral surface of cotyledon. There was, however, merely 6.66 % representation of RN type on dorsal surface of cotyledon. The three types of lithocysts were, however, present on leaf. NN type of lithocysts was 50-58% on ventral and dorsal surfaces. RR and RN types were around 20-25%. There were three types of trichomes 1. Non-glandular uniseriate multicellular larger trichomes, 2. Smaller conical trichomes and 3. Sessile glandular trichomes. Size of normal diacytic stomata was found not to vary on different surfaces of the seedling. Stomatal size was of 25.80 ± 14.85 μm on the dorsal surface of leaf and 27.5 x 14.85 μm on the ventral surface. Foliar stomata had sinuous subsidiaries with wavy anticlinal walls. On leaf surface, besides diacytic stomata, anisocytic and staurocytic stomata were also seen – of course in low number. SEM provided images of the cystoliths and druses. Scanning through EDS attached to the SEM facilitated the elemental composition of the leaf, in the region of cystoliths and the polymorph presumably aragonite, indicated that CaCO 3 entered in the composition of the cystolith and the druses.

The fruit-, brood-and seed–size and seed packaging cost have been investigated in Albizia lebbeck (L.) Benth. by studying 100 pods from each of the three mother trees. The length of pod from the three plants (A, B and C) averaged to 19.84 ± 0.3532, 24.48 ± 0.5014 and 21.54 ± 0.3062 cm, respectively with an overall mean of 21.96 ± 0.25cm. The mean weight of pods from plants A, B and C was 3.42 ±0.0984, 3.66 ± 0.092 and 3.69 ± 0.101g and varied by 28.8, 25.3 and 29.62%, respectively. Six pods yielded no seeds. From remaining 294 pods a total of 2393 seeds were recovered. The waste seeds amounted to 13.29, 18.79 and 19.6 % of the total seeds in three mother plants, respectively. In all, 17.28% of the seeds were in waste class. Of 2393 seeds recovered in all, 39% were medium-sized (100-150 mg class), 19% were in very large category and 19% in the category of small seeds. Pod-based inter-tree similarity varied from 77.95 to 84.47% among the three trees. Brood size in A. lebbeck based on 294 pods averaged to 8.14 ± 0.156 seeds per pod varying around 32.78% (range: 1-16). Brood size in 73 healthy pods was asymmetrical around the grand mean of 9.26 ± 0.215 (CV: 19.80%). Brood size distribution was negatively-skewed. The seed weight distribution from composite sample of 2383 seeds (from 294 pods) was somewhat negatively skewed with mean seed weight 123.026 ± 0.1811 mg. The seed weight varied by 32.2 % (ranging from 14 to 245.0 mg). The weight of individual seed from healthy pods of three mother plants (30 pods from A, 30 pods from B and 13 pods from C) averaged to 119.90 ± 0.352, 134.52 ± 0.565 and 135.57 ± 0.668mg, respectively with a variation of 22.43 ± 2.14, 26.31 ± 1.75 and 23.19 ± 3.19%, respectively. Seed packaging cost, SPC1, in three mother plants averaged to 2.294 ± 0.1488, 2.4145 ± 0.1488 and 2.8150 ± 0.03018 g pericarp mass.g-1 seeds in mother plants A, B and C, respectively. The SPC1 varied among the pods around 35.53 and 33.75 % in mother A and B and 38.65% in plant C. The seed packaging cost, SPC2, was 0.2647 ± 0.1235, 0.2965 ± 0.01031 and 0.2923 ± 0.0234 g pericarp mass.seed-1 in three mother plants, respectively. SPC1 distributed normally in plant A and B. SPC2 varied 25.56% in plant A, 18.60% in plant B and 28.91% in plant C. SPC1 and SPC2 didn't vary significantly among the mother trees but varied substantially within trees. The results are discussed in view of available literature.

Large seed size is a trait associated with plant species of mature, closed habitats, and is thought to supply an ample nutrient reserve necessary for seedling establishment. While this relationship has been shown for annuals and short-lived perennials, it is poorly documented for trees. A comparative method was used to determine whether North American temperate tree species which typically establish in shady conditions have larger seeds than those requiring more open conditions. Both angiosperms (hardwoods) and gymnosperms (conifers) were involved in the study. A significant relationship was found between large seed mass and shade-tolerance for angiosperms, but not for gymnosperms. These contrasting results seem to relate to unique evolutionary opportunities or constraints in different taxa. The absence of a relationship for gymnosperms is discussed in terms of character traits which might prevent seed size selection in response to shade. The finding for angiosperms underlines the i...

High-density herbivore species often play an important role in forest regeneration. Native sika deer (Cervus nippon yakushimae) inhabit a high density (51.5–63.8 head/km2, estimated by a pellet count method) area in the western part of a lowland natural forest on Yakushima Island, Japan. To test experimentally the impact of sika deer on the mortality and the survivability of current-year seedlings, which are at a more vulnerable stage than the later stages, we constructed fenced exclosures, planted seeds of nine sapfruit tree species and compared the mortality and the survivability of current-year seedlings between fenced and unfenced quadrats. Large seeded species had significantly greater survivability in fenced quadrats than in unfenced quadrats. However, the survivability disagreed with feeding preferences. Sika deer activity increased seedling mortality of large-seeded species more than that of small-seeded species, and did not decrease much seedling survivability of not-preferred species. We found that the physical disturbance by the high density of sika deer resulted in mortality for both preferred and not-preferred species, and that deer herbivory was important for preferred species.