Fruits aid angiosperm seed dispersal by wind or by animals Fruit development Ovule àseed Entire ovary including ovules à fruit Ovary wall à pericarp The pericarp usually has three layers The exocarp is the outer layer the skin or peel. The middle layer is the mesocarp, or flesh. The innermost layer, endocarp, can be either tough or quite thin. An avocado fruit Fleshy fruits: Berry Fruits can be dry of fleshy Fleshy ovary wall One or multiple carpels What animal disperse seeds of these plants? Fleshy fruits: Drupe - one ovary Similar to berry but has hard endocarp Often consumed by animals, "pit" is passed A coconut is a drupe Liquid and solid endosperm Provide maximum attraction to animals with minimum danger to the seed. Cherry Plum Peach 1
monocot or dicot? how is it dispersed? Flower parts other than the ovary can become part of the fruit Ovary superior, fruit made of ovary only Ovary inferior, receptacle can become part of the fruit Fleshy fruits from inferior ovary: pome Fleshy fruits from inferior ovary: pepo Apple Pear pumpkin Similar to pome but have thick outer rind Seed dispersal of North American squash by mastodons, woolly mammoth, and elephants Wild squash seeds retrieved from the droppings of mastodons Fleshy fruits Receptacle develops into part of the fruit Extinct Extinct Fruit developed from the ovary only 2
Dehiscent dry fruits: capsules Developed from ovary fused by multiple carpels Dehiscent dry fruits: legume 1 ovary, 1 carpel Breaks open along both sides Poppy capsule Sun flowers and relatives pericarp seed ray flowers disk flowers one ovary one ovule Indehiscent dry fruits: achene One seed per fruit Developed from a single carpel Seed coat is not adherent to the pericarp Fig. 14-21, p. 224 Dry fruits 1 carpel multiple carpels Dehiscent Indehiscent By definition, an indehiscent fruit: a. is fleshy. b. has a single carpel. c. does not break open at maturity. d. has an inferior ovary. 1 carpel multiple carpels 3
Flowers or ovaries may be clustered fruits develop in a group druplets Aggregate fruit one flower, multiple ovaries Multiple fruits are developed from multiple flowers pineapple is a multiple fruit Aggregate fruit receptacle ripens Flowering plants diversity There are benefits beyond dispersal for seeds distributed by animals. A seed may be deposited and find itself in a small (or large) mound of organic fertilizer. Amborella Water lily Magnolia Monocots Eudicots flower and fruit Note that this is a much simplified tree! 4
Basal angiosperms: contain the living descendants of several groups that originated while angiosperms were still a young clade. Have not remained static evolutionarily and have not preserved all ancestral features intact. Basal angiosperms Amborella Water lily Magnolia Monocots Eudicots According to the angiosperm phylogeny below, which of the following is INCORRECT? a. Species of Magnolia are more closely related to eudicots than to water lilies b. Species of Magnolia are more closely related to monocots than to eudicots c. Eudicots and Amborella are equally related to common ancestor of all angiosperms d. Water lilies, Amborella, and Magnoliads are examples of basal angiosperms Amborella Water lily Magnolia Monocots Eudicots flower and fruit Basal angiosperms: Amborella Wood contains tracheids but no vessels Dioecious (although vestigial parts indicate a monoecious past) petals and sepals not differentiated (tepal) Tepals arranged in spirals Native to New Caledonia Basal angiosperms: Water lilies Adapted to wetlands with floating leaves and flowers Large flowers with many tepals, stamens, and carpels arranged in spirals Female flower Male flower Series of tepals and stamens of water lilies, showing the transition. General trends of character evolution in angiosperms Basal angiosperms: Magnolia Large flowers with spiral arranged tepals, stamens, and carpels. Leaf veins Secondary growth Vascular bundles Root Flower parts Arrangement Tepal or sepal+petal Cotyledon Basel angiosperms Monocots Eudicots 5
Basel angiosperms Monocots Eudicots Leaf veins net parallel net Basel angiosperms Monocots Eudicots Secondary growth most species no some species Vascular bundles varies scattered in rings Basel angiosperms Monocots Eudicots Flower parts many 3 4 or 5 Arrangement spiral whorls whorls Tepal or sepal+petal tepal tepal sepal+petal Monocots, like palms, don t have true wood (just lots of fibers embedded in pith) Eudicots are defined using a single characteristic: tricolpate pollen All eudicots have it and no other plants have it Monocots: Grass Grass flower: adaptation to wind pollination tricolpate pollen in eudicots monocolpate pollen in basal angiosperms and monocots 6
More examples of monocots Examples of eudicots All of the following are true for monocots EXCEPT Asparagus: basal angiosperm, monocot, or eudicot? a. flower parts usually in threes or multiples of three. b. pollen grains have one pore. c. vascular tissue arranged in a ring. d. veins in leaf are parallel. Lecture 23 Study Guide Which of the following do NOT have single-pored pollen? a. monocots b. Amborella c. Water lily d. eudicots The ovule develops into the seed, the ovary develops into the fruit, and the ovary wall develops into the pericarp in fruits. There are potentially 3 layers in the pericarp, the exocarp (skin), the mesocarp (flesh), and the endocarp which might be hard. Fleshy fruits are divided by those developed from a single ovary only, or from an inferior ovary plus additional floral parts (usually the receptacle). Dry fruits can be dehiscent or indehiscent. You don t need to remember names of the specific types of dry vs. fleshy fruits. Compound fruits are developed from multiple ovaries. Name two compound fruits: strawberry (receptacles+ovaries from a single flower) and pineapple (multiple flowers). 7
Amborella has flowers but lacks vessel elements. It is a member of basal angiosperms. Other basal angiosperms are water lilies and magnolias. Basal angiosperms have net venation, most species have secondary growth, taproot, vascular bundles can be scattered and/or in rings, flower parts often many with spiral arrangement, lack of differentiation between sepal and petal, two cotyledons. Features of eudicots: net venation, flower parts in fours or fives, two cotyledons, stem vascular bundles in rings. Eudicots are defined using a single characteristic: tricolpate pollen. All eudicots have it and no other plants have it. Basal angiosperms and monocots have monocolpate pollen. Characteristics of monocots: single cotyledon, leaves have parallel veins, flower parts in threes, stems have scattered vascular bundles, absence of secondary growth, fibrous root system Flower morphology interactive quiz http://digitalfirst.bfwpub.com/principles_of_life/act_2105_flower_morpholo gy.html 8