Why Do Plants Wilt?
You leave forِ work inِ the morning andِ your plant looksِ perfectly happy, butِ by theِ time youِ comeِ home, it’s sad andِ droopy.
So whyِ doِ plants wilt? Usually becauseِ they areِ thirsty!
Many nonwoody plants rely almost exclusively onِ water pressure, orِ turgor, withinِ theirِ cells toِ keepِ them erect.
However, plants areِ constantly losing water throughِ small openings inِ their leaves (called stomata) inِ a process knownِ asِ transpiration.
On a hot, dry day (or afterِ several days withِ noِ rain orِ watering), transpiration causesِ more water toِ beِ lost thanِ isِ coming in, andِ the water balance withinِ theِ plant canِ get thrown off.
There areِ alsoِ a number ofِ plant diseases, knownِ collectively asِ “wilt,” thatِ causeِ plants toِ wilt andِ discolor.
These infections canِ beِ caused byِ viruses, bacteria, orِ fungi, andِ many ofِ these diseases willِ kill theِ plant ifِ left untreated.
Many important food crops areِ susceptible toِ wilt diseases, butِ modern breeders haveِ developed resistant strains andِ varieties forِ a number ofِ these plants.
Finally, someِ plants, especiallyِ legumes, wilt atِ night—a phenomenon knownِ asِ nyctinasty.
The leaves ofِ manyِ of theseِ species areِ fitted withِ jointlike growths called pulvini, whichِ allowِ the leaves orِ leaflets toِ wilt inِ response toِ darkness andِ temperature.
The turgor pressure inِ the pulvini isِ largely regulated byِ a chemical photoreceptor thatِ triggers water toِ move fromِ the joints atِ night andِ refills themِ duringِ the day.