ACID AND BASE SCARIFICATION PROMOTES THE GERMINATION OF THREE FORBS IN THE BAPTISIA GENUS JACK ZINNEN

ACID AND BASE SCARIFICATION PROMOTES THE GERMINATION OF THREE FORBS IN THE BAPTISIA GENUS JACK ZINNEN

AGENDA Research background Relevant past studies Methodology Results Conclusions/Implications Gifts

RESEARCH BACKGROUND Many tallgrass prairie species have mechanisms in order to prevent premature germination (Gardner 2011) Most forbs refuse to germinate without experiencing winterlike conditions

IN ESSENCE Many prairie seeds are recalcitrant Most will require special attention in order to grow plugs Winterlike conditions can be mimicked with cold moist stratification to promote germination Andropogon gerardii Tradescantia ohiensis

WAYS TO PROMOTE PRAIRIE SEED GERMINATION Cold moist stratification (most common) Hot water treatment Scarification

SCARIFICATION Damaging the seed coat by abrasion Hastens or activates germination for tough seeds (legumes) Can be done mechanically or chemically

SPECIES SELECTION: THE BAPTISIA GENUS High quality prairie forbs Very recalcitrant seeds I was interested in utilizing chemical scarification to promote their immediate germination

BREAK THE FORTRESS CHALLENGE

SPECIES SELECTION Species were within range of my home state Species are valuable in prairie restorations Blue wild indigo Baptisia australis Cream wild indigo Baptisia bracteata White wild indigo Baptisia alba

PAST STUDIES Stewart and McGary (2010) used acid scarification on New Jersey tea (Ceanothus americanus) Acid treatments promoted consistent germination, but inferior to hot water treatments

PAST STUDIES Boyle and Hladen (2005) studied germination aspects of B. australis Studied mechanical scarification, hot water treatment, and acid scarification Found that treating seeds with concentrated sulfuric acid for 20-80 minutes yielded rapid and uniform germination

PAST STUDIES Boyle and Hladen (2005) inspired the protocol for my research

RESEARCH PROTOCOL Chose three species based on range, relative commercial/restoration value, and past experiences growing each species Seed was purchased from Prairie Moon Nursery- (mechanically unscarified!)

RESEARCH PROTOCOL Acid scarification performed with conc. sulfuric acid 1M NaOH solution also used for three species to compare acid vs. base scarification

TREATMENTS Acid and base treatments plus control (tap water) Time exposed to chemical scarification was independent variable Chemical scarification exposure times mirrored Boyle and Hladen: 20, 40, 60, 90 minutes.

TREATMENTS Approx. 80 seeds of each species added to 30mL of sulfuric acid, sodium hydroxide, or tap water solution After scarification time was up, seeds were sieved from beaker, washed with tap water, and planted immediately

RESEARCH PROTOCOL Unlike Boyle and Hladen (2005), I used horticultural growing trays for germination Split plot design: assigned treated seeds to randomized cell numbers Marked treatment variations with color-coded toothpicks

COUNTING GERMINATION EVENTS Flats were watered in heated greenhouse for 21 days (Boyle/Hladen) Marked cells showing signs of germination were counted

B. AUSTRALIS Germination (%) Germination (%)

Germination (%)

B. BRACTEATA Germination (%) Germination (%)

B. ALBA Species: balba, Treatment type: acid Species: balba, Treatment type: base Germination (%) Germination (%) Time exposure Time exposure

CONCLUSIONS Acid scarification is a highly reliable way for promoting fast Baptisia germination B. alba and B. bracteata have tougher seeds than B. australis Basic scarification was relatively unreliable besides in B. australis (increase base conc.?)

IMPLICATIONS Commercial/hobbyist bypassing of waiting for cold moist stratification Greater need for scarification of B. bracteata and B. alba Other prairie seeds?

REFERENCES Boyle, T., and Hladen, K. 2005. Influence of seed size, testa color, scarification method, and immersion in cool or hot water on germination of Baptisia australis (L.) R. Br. Seeds. Horticultural Science 40: 1846-1849. Gardner, H. 2011. Tallgrass Prairie Restoration in the Midwestern and Eastern United States: A Hands-on Guide. Springer Science. Stewart, R., and McGary, I. 2010. Brief exposure to boiling water combined with cold-moist stratification enhances seed germination of New Jersey tea. HortTechnology 20: 623-625.

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