02427nas a2200193 4500008004100000245009300041210006900134300001300203490000800216520181800224653000802042653001302050653002002063653002802083653002302111100001402134700001902148856006602167 2015 eng d00aBud bank dynamics and clonal growth strategy in the rhizomatous grass Pascopyrum smithii0 aBud bank dynamics and clonal growth strategy in the rhizomatous  a395 -4050 v2163 a

Recruitment of rhizomatous perennial grass ramets primarily occurs from the belowground bud bank. Investment in guerilla versus phalanx growth is determined by bud availability, development, and spatial distribution. The tiller and bud bank dynamics of Pascopyrum smithii, a dominant rhizomatous grass of the northern mixed-grass prairie, were examined in South Dakota throughout an annual cycle to assess the investment in guerilla versus phalanx growth and the role of different bud populations in renewal versus regenerative functions and vegetative spread via rhizomes. Pascopyrum smithii invested substantially in both phalanx and guerilla tiller production. However, investment in rhizome production before tiller recruitment prioritized guerilla over phalanx growth. Annual tiller recruitment of P. smithii was capable of flexible timing, occurring in either spring or fall. Renewal buds, from which rhizomes and tillers were recruited, primarily consisted of the youngest generation of buds borne at the base of tillers. Although rhizome axillary buds and older tiller axillary buds were rarely used in annual tiller recruitment, they provided a sizable reserve (regenerative) bud bank. The spatial distribution of bud development produced the mixed guerrilla–phalanx growth pattern and flexible tiller recruitment timing of P. smithii. Therefore, P. smithii is capable of employing both conservative and foraging growth strategies which will facilitate its persistence under local neighborhood variability and changing resource availability associated with environmental change. Understanding the spatial distribution of buds as determined by rhizome architecture is essential to understanding the distribution and composition of species within plant communities dominated by clonal species.

10aBud10aGuerilla10aPhalanx Rhizome10aVegetative reproduction10aWestern wheatgrass1 aOtt, J.P.1 aHartnett, D.C. uhttps://link.springer.com/article/10.1007%2Fs11258-014-0444-602844nas a2200133 4500008004100000245013000041210006900171300001100240490000800251520237100259100001402630700001902644856004702663 2015 eng d00aVegetative reproduction and bud Bank dynamics of the perennial grass andropogon gerardii in mixed-grass and tallgrass prairie0 aVegetative reproduction and bud Bank dynamics of the perennial g a14 -340 v1743 a

Plant species with wide distributions may differ in their population dynamics across their range, especially in contrasting habitats. Most tiller recruitment of perennial grasses occurs vegetatively from the belowground bud bank rather than from seed. Seed reproduction often occurs under a narrower range of environmental conditions than vegetative reproduction. As a result flowering and seedling recruitment patterns of a species often differ between contrasting habitats and across its range. How vegetative reproduction and bud bank dynamics of a species vary between contrasting habitats has not been well studied and could explain the differences in its persistence and productivity between habitats. Therefore, the vegetative reproduction and dynamics of Andropogon gerardii, a dominant C4 perennial grass of the Great Plains of North America, were compared between tallgrass and northern mixedgrass prairie habitats. Bud production and tiller recruitment in 10 populations were examined throughout an annual growing cycle in the northern mixedgrass prairie of South Dakota. Bud bank characteristics, and individual and population performance were compared with previous work conducted in Kansas tallgrass prairie. Stage-structured matrix models examined population growth rates. Andropogon gerardii tillers produced lower numbers of buds and had lower flowering rates in mixedgrass prairie populations. The annual phenology of bud and tiller development was also contracted to fit within the shorter growing season in northern mixedgrass prairie. However, bud longevity and bud bank age structure were similar between habitats, both having buds that lived for > 2 y and multi-aged bud banks. Similar population growth rates occurred in both habitats despite lower individual performance of both flowering and vegetative reproductive capacity (i.e., bud production) in mixedgrass prairie populations. Lower regional productivity of A. gerardii in northern mixedgrass prairie than in tallgrass prairie does not appear to be due to differences in bud and tiller population growth. Instead, sparse or patchy suitable habitat and/or reduction in tiller size may explain its reduced productivity. Lower population growth rates may be observed in other habitats or in years with harsher environmental conditions that further lower individual performance.

1 aOtt, J.P.1 aHartnett, D.C. uhttps://doi.org/10.1674/0003-0031-174.1.1403063nas a2200193 4500008004100000245008900041210006900130260004300199490002200242520242300264653001302687653003102700653002002731653002002751653002802771100001402799700001902813856003702832 2014 eng d00aEcological implications of grass bud bank and tiller dynamics in mixed-grass prairie0 aEcological implications of grass bud bank and tiller dynamics in aManhattan, KSbKansas State University0 vPhD. Dissertation3 a

Perennial grass populations propagate vegetatively via the belowground bud bank. Climate, photosynthetic pathway, and growth form impact bud production, longevity, and dormancy; leading to alterations in bud bank and tiller dynamics. Previous research in mesic C₄-dominated tallgrass prairie revealed that a C₄ grass had greater bud longevity and differing bud bank dynamics than a C₃ species. This study examined the bud bank dynamics of rhizomatous and caespitose grasses in a more arid C₃ dominated prairie to gain insights into how bud banks differ among grass species, growth forms, and environments, and the relationship between bud bank characteristics and grass architecture and growth patterns. The bud bank and tiller dynamics of four perennial grasses in the C₃-dominated northern mixed grass prairie were examined over 15 months. The C₃ caespitose and rhizomatous grasses produced similar numbers of buds per tiller and their bud longevity was [greater than or equal to] 2 years. Tiller longevity drove the turnover within the bud bank of the dominant C₃ caespitose grasses Hesperostipa comata and Nassella viridula. Their polycyclic tillers (tillers that lived for more than one year) created multi-aged bud banks. The rhizomatous C₃ grass Pascopyrum smithii also had a multi-aged bud bank because buds were able to live longer than its annual tillers. Differences between caespitose and rhizomatous C₃ grass bud banks were driven by differences in tiller and rhizome production and spatial distribution. Responses to water availability fluctuations are likely buffered by the maintenance of polycyclic tillers in the caespitose grasses and flexible timing of annual tiller recruitment in the rhizomatous grass. The C₄ rhizomatous grass Andropogon gerardii had similar phenology to populations in its tallgrass prairie range center. Despite declines in bud production per tiller and lowered flowering probability in mixed-grass prairie, A. gerardii maintained a multi-aged bud bank and a positive population growth rate via vegetative reproduction at both the center and edge of its range. Bud bank dynamics of different growth forms and photosynthetic pathways, as they offer insight into the control of grass population dynamics and production, will enhance understanding of the mechanisms by which management practices and environmental change can alter perennial grasslands.

10aBud bank10aGrass; Mixed-grass prairie10aperennial grass10aTiller dynamics10aVegetative reproduction1 aOtt, J.P.1 aHartnett, D.C. uhttp://hdl.handle.net/2097/1727702725nas a2200217 4500008004100000245011300041210006900154300001300223490000700236520204500243653001002288653001502298653001602313653002202329653001202351100001902363700001402382700001702396700001702413856007702430 2013 eng d00aVariation in root system traits among African semi-arid savanna grasses: implications for drought tolerance0 aVariation in root system traits among African semiarid savanna g a383 -3920 v383 a

In arid to semi-arid grasslands and savannas, plant growth, population dynamics, and productivity are consistently and strongly limited by soil water and nutrient availability. Adaptive traits of the root systems of grasses in these ecosystems are crucial to their ability to cope with strong water and/or nutrient limitation and the increasing drought stress associated with ecosystem degradation or projected climate change. We studied 18 grass species in semi-arid savanna of the Kalahari region of Botswana to quantify interspecific variation in three important root system traits including root system architecture, rhizosheath thickness and mycorrhizal colonization. Drought-tolerant species and shorter-lived species showed greater rhizosheath thickness and fine root development but lower mycorrhizal colonization compared to later successional climax grasses and those characteristic of wetter sites. In addition, there was a significant positive correlation between root fibrousness index and rhizosheath thickness among species and a weak negative correlation between root fibrousness index and mycorrhizal colonization. These patterns suggest that an extensive fine root system and rhizosheath development may be important complementary traits of grasses coping with drought conditions, the former aiding in the acquisition of water by the grass plant and the latter aiding in water uptake and retention, and reducing water loss in the rhizosphere. Within species, both rhizosheath development and mycorrhizal colonization were significantly greater in a wet year than in a year with below-average precipitation. The observed patterns suggest that the primary benefit of rhizosheath development in African savanna grasses is improved drought tolerance and that it is a plastic trait that can be adjusted annually to changing environmental conditions. The functioning of mycorrhizal symbiosis is likely to be relatively more important in infertile savannas where nutrient limitation is higher relative to water limitation.

10agrass10amycorrhiza10arhizosheath10aroot architecture10asavanna1 aHartnett, D.C.1 aOtt, J.P.1 aWilson, G.T.1 aSetshogo, M. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1442-9993.2012.02422.x02456nas a2200205 4500008004100000245012000041210006900161300001500230490000800245520175600253653001302009653002702022653002102049653003002070653002302100653002802123100001402151700001902165856006602184 2012 eng d00aContrasting bud bank dynamics of two co-occurring grasses in tallgrass prairie: implications for grassland dynamics0 aContrasting bud bank dynamics of two cooccurring grasses in tall a1437 -14480 v2133 a

Because most shoot recruitment in perennial grasses occurs from belowground axillary buds, bud dynamics determine plant population dynamics and meristem limitation to population growth. Therefore, grassland vegetation responses to environmental change or disturbance may be influenced by interspecific differences in bud banks and the patterns and environmental controls of bud development and demography. We examined bud bank dynamics in Andropogon gerardii and Dichanthelium oligosanthes in tallgrass prairie by enumerating and classifying buds throughout 15 months to determine whether grass buds live for multiple years and accumulate; whether bud natality, dormancy and outgrowth are synchronous or variable; and whether bud bank dynamics differ between these co-occurring species. Andropogon gerardii (a C4 species) maintained a larger dormant bud bank, showed synchrony in bud development and transition to tiller, and its buds lived for multiple years. Thus, multiple previous years’ bud cohorts contributed to recruitment. By contrast, D. oligosanthes (a C3 species) maintained a smaller dormant bud bank, had asynchronous bud development with active buds present year-round, and its buds lived for 1 year. Buds played different roles in the dynamics of each species, allowing A. gerardii to over-winter and recruit new spring tillers and D. oligosanthes to survive and recruit new tillers following summer dormancy. These differences in bud bank age structure, phenology, and dynamics between these species suggest greater demographic buffering and time-lag effects in A. gerardii populations. Interspecific differences in bud bank structure and dynamics may explain and help predict grassland responses to environmental change.

10aMeristem10aPhotosynthetic pathway10aPlant demography10aPlant population dynamics10aTiller recruitment10aVegetative reproduction1 aOtt, J.P.1 aHartnett, D.C. uhttps://link.springer.com/article/10.1007%2Fs11258-012-0102-902344nas a2200253 4500008004100000245013700041210006900178300001300247490000700260520137100267653001301638653001301651653001601664653001401680653003501694653001201729653001401741653002101755100001901776700001401795700001401809700001701823856025001840 2012 eng d00aCoping with herbivory at the juvenile stage: Responses to defoliation and browsing in the African savanna tree Colophospermum mopane0 aCoping with herbivory at the juvenile stage Responses to defolia a161 -1690 v283 a

Responses of plants to herbivory are dependent on the type of damage and the ontogenetic stage of the plant. We compared the effects of stem pruning and defoliation on seedlings of Colophospermum mopane, an ecologically important tree species widely distributed in southern Africa. The growth of 160 greenhouse-grown juveniles were measured for 6-mo after germination and then 6-mo after treatments including 50% defoliation, 100% defoliation, 50% stem pruning and controls. Pruning resulted in 30% reductions in total leaf area, height and biomass. Partial defoliation resulted in 30% reductions in total leaf area and plant biomass. However, complete defoliation resulted in a 30% increase in biomass production, a doubling in leaf and lateral branch number, a 45% reduction in leaf size, and no change in total leaf area. Thus, completely defoliated seedlings showed greater performance than those that were only partially defoliated, indicating that C. mopane has become adapted to the chronic and severe defoliation inflicted by Imbrasia belina caterpillars. Comparison of our results with other studies indicates that C. mopane seedlings are less herbivory-tolerant than adults and that pruning has more negative effects than defoliation. Thus, seedling browsers may constrain recruitment in C. mopane, influencing its population dynamics and abundance.

10aBotswana10abrowsing10adefoliation10aHerbivory10aPlant–herbivore interactions10asavanna10aseedlings10atree recruitment1 aHartnett, D.C.1 aOtt, J.P.1 aSebes, K.1 aDitlhogo, M. uhttps://www.cambridge.org/core/journals/journal-of-tropical-ecology/article/coping-with-herbivory-at-the-juvenile-stage-responses-to-defoliation-and-stem-browsing-in-the-african-savanna-tree-colophospermum-mopane/5B519E0F1B9BD889D4905FD311257D9A02046nas a2200181 4500008004100000245014300041210006900184300001300253490000700266520142700273653001301700653001501713653003101728653001401759100001401773700001901787856005801806 2012 eng d00aHigher-order bud production increases tillering capacity in the perennial caespitose grass Scribner's Panicum (Dichanthelium oligosanthes)0 aHigherorder bud production increases tillering capacity in the p a884 -8900 v903 a

The persistence and dynamics of perennial grass populations strongly depend on tiller recruitment from the bud bank. Because of the structural organization of grasses as populations of phytomers, bud production and tillering are constrained by morphology. An infrequent trait observed in only a few caespitose grasses is the branching of buds to produce higher-order buds prior to tiller development. We studied bud bank dynamics in Dichanthelium oligosanthes (Schult.) Gould a C3 perennial caespitose grass widely distributed in the eastern Great Plains. A hierarchy of bud development occurred in D. oligosanthes, with primary buds branching to produce secondary, tertiary, and quaternary buds. This higher-order bud production increased the overwintering propagule supply for spring recruitment by 4.5 times, and more than half of successful tiller recruits originated as higher-order buds. The temporal patterns of higher-order bud production and development suggest that growing season length may be an important factor determining the extent of higher-order bud production and subsequent year tiller natality in D. oligosanthes. Higher-order bud production likely has important consequences for the population dynamics of grasses. It may increase bud bank densities and tillering capacity, buffer population dynamics, and increase intraclonal tiller densities and resource consolidation in caespitose grasses.

10aBud bank10abunchgrass10aDichanthelium oligosanthes10atillering1 aOtt, J.P.1 aHartnett, D.C. uhttp://www.nrcresearchpress.com/doi/10.1139/b2012-04302491nas a2200229 4500008004100000245010200041210006900143300001300212490000700225520176600232653001301998653001302011653001202024653002802036653002802064100002002092700001402112700001702126700001602143700001902159856008302178 2012 eng d00aInterspecific variation in bud banks and flowering effort among semi-arid African savanna grasses0 aInterspecific variation in bud banks and flowering effort among  a127 -1330 v833 a

Population viability and productivity of grasses in southern African savannas are dependent upon both successful seed production and tiller recruitment from the belowground bud bank. Relative recruitment rates from buds versus seeds influence population dynamics, genetic diversity, and patterns of vegetation productivity. We assessed patterns in bud bank size and flowering effort in fourteen semi-arid savanna grass species in the Kalahari region of Botswana. There was high inter-specific variability and between-year variability in flowering effort (percentage of tillers flowering). Bud production (number of buds per tiller) exhibited high inter-specific variability, but was more consistent between-years than flowering effort. Relative allocation to flowering versus bud production varied with life history, with longer-lived perennial grasses showing higher bud production and lower flowering effort relative to shorter-lived grasses. Several species showed higher bud production and lower flowering effort in a wet year compared to a dry year, and grass species that are regularly grazed maintained significantly larger bud banks than non-grazed species. These differential demographic responses among co-occurring species suggest that environmental change in semi-arid savannas may alter the composition, relative abundances and diversity of grasses, and that the maintenance of a belowground bud bank is an important factor influencing their resiliency, their capacity to recover from grazing and/or drought, and their persistence and sustainability under changing environmental conditions. Meristem-limitation in species that maintain few viable buds may constrain their population viability under changing conditions in semi-arid savannas.

10aBud bank10aMeristem10aPoaceae10aReproductive allocation10aVegetative reproduction1 aDalgleish, H.J.1 aOtt, J.P.1 aSetshogo, M.1 aMuzilla, M.1 aHartnett, D.C. uhttps://www.sciencedirect.com/science/article/pii/S0254629912001275?via%3Dihub02623nas a2200241 4500008004100000245016100041210006900202300001500271490000700286520182700293653001502120653001702135653001302152653001302165653001302178653002002191653002302211653001302234653002802247100001402275700001902289856007302308 2011 eng d00aBud production and dynamics of flowering and vegetative tillers of the perennial grass Andropogon gerardii (Poaceae): the role of developmental constraints0 aBud production and dynamics of flowering and vegetative tillers  a1293 -12980 v983 a

•Premise of the Study: Perennial grasses maintain aboveground tiller populations through vegetative reproduction via belowground buds and sexual reproduction via seed. The maintenance of a bud bank has important demographic consequences for perennial grasses. A tradeoff between these reproductive modes would be expected for a plant with limited resource availability. However, the ontogeny of the tiller could affect its ability to allocate between these two modes of reproduction. •Methods: Vegetative bud production and dynamics and tiller production were examined biweekly through an annual cycle on vegetative and flowering tillers of Andropogon gerardii. •Key Results: Andropogon gerardii maintains a large reserve of dormant buds. Although vegetative and flowering tillers had similar bud phenology, flowering tillers produced larger numbers of buds of larger size, and transitioned a larger proportion of their buds to tiller, than did vegetative tillers. Therefore, a negative consequence of sexual reproduction on vegetative reproduction was not evident at the tiller level. A size threshold for floral induction likely exists that results in flowering tillers having more buds per tiller than vegetative tillers. The increased bud outgrowth of flowering tillers could be a result of their larger bud size or weaker apical dominance as compared to vegetative tillers. •Conclusions: Plant development can place significant constraints on tradeoffs between the reproductive modes in perennial grasses and could affect their plasticity in plant reproductive allocation. Differences in developmental phenology and bud production between flowering and vegetative tillers may influence grass responses to environmental changes such as altered precipitation regimes or resource availability.

10aallocation10aaxillary bud10aBud bank10aMeristem10aontogeny10aperennial grass10aTiller recruitment10atradeoff10aVegetative reproduction1 aOtt, J.P.1 aHartnett, D.C. uhttps://bsapubs.onlinelibrary.wiley.com/doi/full/10.3732/ajb.100026400436nas a2200121 4500008004100000245007100041210006900112260004300181300001000224490001400234100001400248856005200262 2009 eng d00aBud bank morphology, dynamics, and production in perennial grasses0 aBud bank morphology dynamics and production in perennial grasses aManhattan, KSbKansas State University a1 -930 vMS Thesis1 aOtt, J.P. uhttp://krex.k-state.edu/dspace/handle/2097/1807