*Obtaining enough

water, When fluid no longer bathes the entire surface.
*Transporting water and dissolved salt from restricted areas of intake to other parts of the plant.
*Prevention of excessive loss of water by evaporation.
*Maintaining a sufficiently extensive moist surface for gas exchange in air.
*Supporting a large plant body against the pull of gravity in the absence of buoyancy supplied by a aqueous medium.
*Carry out reproduction when there is little water through which flagellated sperm may swim and when  zygote and embryo are in danger of desiccation.
*Withstand extreme flunctuations in temperature, humidity, light and other environmental factors.

SOLUTIONS
*Development of various categories of water absorbing organs, such as rhizoids, and proper root in bryophytes and higher plants.
*Development of simple conducting tissue, e.g cytoplasmic filament to highly complex tissues of vascular plants.
*possession of waxy cuticle on exposed surfaces, various adaptation of plant parts prevent evaporation e.g spines sunken stomata, succulent stems/leaves prostrate habit, etc.
*possession of strengthening tissues such as sclerenchyma, collenchyma, etc or adaptation such as twining, climbing or prostrate/running habits.
*Angiosperms and gymnosperms developed seeds and pollen. Lower plants developed protective jacket of sterile cells for their reproductive function.
*Flunctuation/extremes in weather condition are combated by various adaptations to specific habits. If such as hydrophytic and xerophytic condition.