Seed size and seedling ontogenetic stage as modulators of damage tolerance after simulated herbivory in a woody exotic species

2019 ◽  
Vol 67 (2) ◽  
pp. 159 ◽  
Author(s):  
E. Agostina Lorca ◽  
Ana E. Ferreras ◽  
Guillermo Funes

Herbivory is one of the most important threats that plants face during early stages of development. Previous studies have indicated that seed size and seedling ontogeny strongly influence the response to herbivory at the seedling stage. However, little is known about their interactive effect. We simulated herbivory on seedlings of the exotic Gleditsia triacanthos L. and evaluated the combined effects of seed size and ontogenetic stage at which herbivory occurred on tolerance to herbivory. A greenhouse experiment was performed, with three non-overlapping levels of seed size. Seedlings from each seed size were clipped at two ontogenetic stages (two and five leaves). After three weeks, seedling survival, height, leaf number and dry biomass were measured. Damaged seedlings were not able to reach the size of the undamaged ones. Seedlings from small seeds showed the lowest values in most of the growth variables. Seedlings cut at two-leaf stage showed a higher compensation capacity than those cut at five-leaf stage. Seedlings from large seeds cut at ontogenetic stage I showed the highest compensation capacity in most of the variables. Partly compensating herbivory at this stage may be an advantage for the expansion of this exotic species to new areas.

2017 ◽  
Vol 6 (2) ◽  
pp. 5256
Author(s):  
Daryoush Shafiei ◽  
Prof. Basavaiah*

In mulberry (Morus spp.), the process of selection of promising hybrids from F1 population requires the screening of a large number of progenies and a long period. To develop a simple and faster approach for screening, studies were conducted using F1 seeds of two crosses. The details of screening studies conducted in relation to seed-size and seedling-size are reported separately in two parts. In this part, the F1 seeds were size-graded as small, medium and large seeds; their progenies were raised separately and screened in nursery. There was a considerable degree of variation in size of seeds and medium-size class seeds were in high percentage in both the crosses. The length, width and weight of seeds were also varied between the seed size classes significantly in both the crosses. The seed size classes differ with high significance in shoot length and Root collar diameter and also differ significantly in root length and weight of seedlings. The positive correlation between the seed size and growth of seedlings, seed size and germination, seed size and seedling survival in nursery indicated that size-grading of seeds and rejection of small seeds in the beginning of screening process may help to increase the efficiency of screening by increasing the chances of getting superior hybrids from limited progenies. However, confirmation on the performance of large seedlings from small seed size class may help to draw conclusion. Hence, the studies are continued with size- grading of seedlings in the next part of screening study.


Botany ◽  
2016 ◽  
Vol 94 (8) ◽  
pp. 635-642 ◽  
Author(s):  
Zoryana Shibel ◽  
Stephen B. Heard

Understanding the combined effects of stressors on plants is important for understanding how they will tolerate herbivory and other damage under unfavorable conditions. When two stresses have synergistic effects, plants may experience particularly strong impacts. We examined individual and combined effects of drought stress and clipping (simulated herbivory) on two species of goldenrods (Solidago altissima L. and S. gigantea Ait.). Each stress reduced production of most plant structures, with drought stress having stronger impacts than clipping. The effects of the two stresses were additive for S. gigantea but synergistic for S. altissima, at least for aboveground biomass and inflorescence biomass. Both species, when under stress, reallocated resources toward asexual reproduction (rhizomes) and away from sexual reproduction (inflorescences). Our results suggest that even closely related plants may tolerate damage differently when under abiotic stresses, and that predicting the additive vs. synergistic action of combined stresses will be difficult.


1994 ◽  
Vol 72 (6) ◽  
pp. 853-859 ◽  
Author(s):  
Anne Tolvanen

Insect and microtine rodent herbivory (defoliation and branch clipping, respectively) were simulated in stands of the deciduous Vaccinium myrtillus L. and evergreen V. vitis-idaea L. Rhizome connections around the treated plots were either left intact or severed. Recovery in the plots was monitored for two growth seasons, from 1991 to 1992. It was hypothesized that the evergreen V. vitis-idaea would suffer more from the simulated herbivory treatment than V. myrtillus, but that severing the rhizome connections would decrease recovery of both species, because clonal integration is disrupted and wounding may have a harmful influence on growth. After two growth seasons, recovery was complete from simulated herbivory in V. myrtillus, whereas the new dry biomass was reduced slightly (22 – 37%) or significantly (49%) compared with that of the control in V. vitis-idaea. Rhizome severing reduced the growth of the branches and ramets and the aboveground dry biomass by 34% compared with that of the unsevered control in V. myrtillus. In the evergreen V. vitis-idaea, severing slightly reduced growth, the effect being significant only in the clipped treatment. The results suggest that the deciduous V. myrtillus recovers more rapidly from simulated herbivory than the evergreen V. vitis-idaea. Rhizome severing is more detrimental to the growth of V. myrtillus, but less detrimental to recovery from simulated herbivory. Sexual reproduction decreases more in V. vitis-idaea than in V. myrtillus after damage. Key words: compensation, growth form, herbivory, rhizome severing, Vaccinium


1985 ◽  
Vol 33 (2) ◽  
pp. 197 ◽  
Author(s):  
M.E. Lawrence

The reproductive biology of 28 native and four exotic species of Senecio is described in terms of their breeding system, longevity, habitat stability, seed size and number, dispersal potential and seedling establishment. Nineteen species (15 perennial, 2 annual, 2 ephemeral) are self-incompatible, 13 are self-compatible (4 perennial, 7 annual, 2 ephemeral) and nearly all occur in unstable environments. The success of the perennial species in unstable environments perhaps reflects the fact that they all reach sexual maturity within 1 year of germination and, provided populations of self-incompatible species are large enough, they can set seed in the first year.


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