Touch your plants and they’ll tell their neighbors

Yearly tree pruning

Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

rest of the paper

Freeloading orchid relies on mushrooms above and below ground

Plants are well known for their deceptive ways, orchids being the worst of the bunch

The non-photosynthesizing orchid species Gastrodia pubilabiata mimics rotting mushrooms or fermented fruit, and is pollinated by fruit flies who mistakenly lay their eggs in its flowers. If there are rotting mushrooms near the orchid, its pollination rate increases. As well as using mushrooms to attract insect pollinators, G. pubilabiata survives by absorbing nutrients from the fungal hyphae of mushrooms. This is the first time a plant has been discovered to depend on mushrooms both above and below ground. more…

Read the paper:
Achlorophyllous orchid can utilize fungi not only for nutritional demands but also pollinator attraction

Sedate a Venus FlyTrap, and It Seems to Lose Consciousness

1 yr old Venus FlyTrap Seedlings

Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested.

Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps

How crafty is your plant?

Allelopathy is the release of organic chemicals that help or harm plants growing nearby by a plant. What is really interesting is that these allelochemicals are not used by the plant except to influence other plants.

One of the best known cases of this happens with walnut trees. Walnut trees produce hydojuglone. When hydrojuglone is exposed to oxygen it causes anything from wilting to death in plants near the walnut tree.

While digging around the net learning about allelopathy I started to wonder just how smart plants might be and stumbled upon: Aspects of Plant Intelligence a paper published in the Annals of Botany in 2003

The more we learn about plants and the chemical signaling inside and sent out from the plant, the less like vegetables they appear to be.

The paper is very readable, you won’t need a science degree to dig through it and worth a read. You’ll not look at your plants the same way again.

See also:
The secret language of plants
Chemical war: How plants starve bugs

Blue is for leaves, red is for flowers

The tip of the leaf of a plant senses blue light and signals the plant to grow in the direction of the blue light.

The red glow of a sunset is what signals the plant when it is time to bloom. A plant kept in a dark closet can be signaled to flower with just a short flash of red light.

Plants use both blue and red light to feed themselves but slightly favor red.

Plants appear mostly green because they are reflecting most of the green light that hits them, it doesn’t get used by the plant.

If your plant is not growing well, try adding more blue light. If you’re not getting flowers try more red light.

Plants release scents to warn other plants of insect attacks

Plants release hundreds of volatile chemicals ( scents ) to both attract and repel insects.

Cabbage butterflies lay their eggs in cabbage. In response the cabbage plants release a scent that attracts two species of moths that feed on cabbage butterflies.

When insects lay eggs in the plant they damage the plant, this damage triggers the plant to release chemicals to protect it from the insects about to hatch and feed on the plant. Some chemicals kill the plant tissue around the egg causing the egg to fall off the plant. Other chemicals attract predators of the insect eggs.

Cabbage family plants make glucosinolate from sugar giving them their well known bitter flavor. This is what acts to fight cancer in people who eat these plants.

Plants containing glucosinolate can be used keep pests away from other crops.Some insects have adapted to be able to deflect the toxins and use these plants for feeding and egg laying.

Plants cry for help when attack expected
PLOS One, Plant volatiles induced by herbivore egg deposition affect insects of different trophic levels