Vegetative Development of PlantsHORT 301 – Plant Physiology

December 4, 2009Taiz and Zeiger – Chapter 16, Smith et al. – Chapter 5

paul.m.hasegawa.1@purdue.edu

Three basic stages of plant development are embryogenesis, vegetative growth/development and reproductive growth/development

Smith et al. (2010) Plant Biology

Genetic programs regulate plant developmentPlant development is affected also by the environment

Smith et al. (2010) Plant Biology

Hartmann et al. Plant Propagation 2002

Pollination and embryogenesis leads to seed development

Graham et al. 2006, Plant Biology

Graham et al. (2006) Plant Biology

Asymmetric and symmetric cell divisions are involved in embryogenesis

Double fertilization causes the formation of the zygote and endosperm

Plant Biology (2010) Smith et al

Stages of embryogenesis

Smith et al. (2020) Plant Biology

Coordinated program is responsible for embryo development

Auxin is a primary regulator of embryogenesisAuxin movement and accumulation establishes polarity that regulates cell patterning

Proembyro

Prosuspensor

Genes involved in embryogenesisAxial patterning

Radial patterning

WOODEN LEG (WOL) encodes a cytokinin receptor and regulates phloem development, wol – no proto-phloem

Ground tissue (cortex and endodermis) development

scr

scr – cortex and endodermis are disturbed (merged)

shr – no endodermis

wol – no phloem

Plant Biology (2010) Smith et al

Seed development/dormancy and germination is regulated by ABA and GA

Smith et al. (2010) Plant Biology

Plant Biology (2010) Smith et al

Smith et al. (2010) Plant Biology

Shoot apical meristem (SAM) is the progenitor of the repeated unit of the shootRepeated unit is leaf, lateral meristem and internode

Shoot apical meristem may not be directly affected by auxin

Coordination of WUSCHEL (WUS) and CLAVATA 3 (CLV3) expression is indicative of genes that regulate cell patterning during shoot development

Shoot apical meristem (SAM) organization and shoot and root development – genetic programs for which numerous important determinants have been identified

Plant Biology (2010) Smith et al

Polar auxin transport regulates shoot elongation

Smith et al. (2010) Plant Biology

Plant Biology (2010) Smith et al.

Lateral suppression reduces branching in tomato and maize

Smith et al. (2008) Plant Biology

Leaf meristem has three developmental axesTip to base, radial, and upper (adaxial) and lower (abaxial) surfaces

Plant Biology (2010) Smith et al

Vertical and horizontal leaf growth

Plant Biology (2010) Smith et al

Root apical meristem (RAM) and zonation

Auxin is involved in root apical meristem cell identity and root development

Root development

Lateral root branching is due to divisions of the pericycle

Senescence/and programmed cell death are an aging process

Soybean plants are similar age but flowers were removed from the plant on the right