What makes a mushroom sprout out of soil soon after monsoon but not after sprinkling water?

What makes a mushroom sprout out of soil soon after monsoon but not after sprinkling water?

A majority of mushrooms that sprout directly from soil during the monsoons belong to the Tricholomataceae family. Calocybe indica, a beautiful and white coloured umbrella shaped mushroom is the most prominent among them. This genus originated from the forests of West Bengal. Today, its variants are cultivated commercially under the popular name 'Milky mushroom'.

Mushroom spores are hyaline, broadly ellipsoidal, thin-walled with prominent apiculis. Under favourable conditions such as low temperature, high relative humidity and faded light, the spores germinate and the mycelial spread resumes. It takes nearly 50 days for the completion of the mycelial spread and subsequent emergence of the sporophores. During the entire period of mycelial spread, very high relative humidity, 25-30 degree Celsius temperature and faint light are necessary. Unlike sprinkling water, monsoon changes the entire microclimate. Sprinkling cannot reduce the atmospheric temperature, control sunshine or maintain high relative humidity for long time whereas the monsoon's prominent effects will be the high or stable relative humidity coupled with decrease in the intensity of sunshine, which are necessary for spawn spread. Mushroom beds, after inoculation with mushroom spawn, should be kept for 30 days under darkness with high atmospheric humidity. After the mycelial spread the plastic cover of the bed is removed, sterilised casing mixture composed of equal quantities of soil, sand and cowdung is loosely spread over the bed. Only faded light is permitted but high humidity is maintained. After about two weeks mushroom start sprouting.

Source: The Hindu

How do carnivorous plants digest their meal and remove the waste after digestion?

How do carnivorous plants digest their meal and remove the waste after digestion?

Carnivorous plants capture small insects and digest them to obtain nutrients . Some of the carnivorous plants catch the insects `actively' by rapid movement of the trap mechanism (for example, Venus fly trap) while a large majority are `passive' catchers where the insect falls into pitcher-like structures (for example, Pitcher plant) or stick on to mucilage (for example, Sundews). Digestion proceeds after catching the insect. Some plant species produce and secrete digestive enzymes on to the trapped insect and digest them. Most of the active trap plants belong to this category. Some plant species depend on bacteria to produce these digestive enzymes. Some plant species use a combination of both the above methods.

Most of the passive trap plants that use mucilage `sticky traps' are associated with `killer bugs' to digest their catch. These insects eat the catch and excrete their faeces on the plant surface. The plants absorb nutrients from the faeces. Amazingly, these associated killer bugs do not get trapped.In active trap plant species, enzyme secretion is triggered upon catching the prey. n Pitcher plants, when the trap is formed, the bottom is filled with a mixture of digestive enzymes, which slowly declines if no insect is trapped. Later, when insects get trapped, enzyme secretion is activated . It was also identified that these plants even adjust the pH (acidity) to favour the digestive enzymes. Some plant species produce free oxygen radicals to non-enzymatically digest proteins (for example, the protein myosin) or to predispose proteins to digestion by proteases.The tough exoskeleton of insects is usually not digested and when traps are open, these are blown away by the wind. In pitcher plant species, these just accumulate at the bottom until the trap decomposes later. All traps have special structures and transporters to absorb nutrients.

Source: thehindu.com

How do plants digest their food? Is there any digestive system in plants?

How do plants digest their food? Is there any digestive system in plants?

The `food' for plants is sunlight, water and air (carbon dioxide and oxygen). Plants have the amazing ability to harvest energy from the sun using chlorophyll and convert it in to chemical energy. They then utilise it to produce carbohydrates such as sugars and starch (`photosynthesis'). These carbohydrates serve as chief energy source for almost all living beings in the world, including plants themselves. Nutrients such as nitrogen, phosphorus, potassium and other micronutrients are taken up by plants in very simple forms and used directly. So, plants do not need a digestive system.

Image source: huffingtonpost.com

Plant cells oxidise the sugars to release carbon dioxide and energy and utilise the energy to drive reactions for normal functions of the cell.In addition, cells use carbohydrates and derived products as building blocks for proteins and lipids (fat). Carbohydrates, proteins and lipids are the chief components of several sub-cellular organelles (parts of a cell). Herbivorous animals derive energy and most of the components necessary for making proteins and fat by eating plants. The only time plants have to `digest' something is when the seed cotyledons breakdown complex molecules in order to provide energy to the germinating embryo. However, certain carnivorous plants do have a very primitive digestive system.

Carnivorous plants are often found in marshy landscapes where they do not get adequate nitrogen. Nitrogen is an essential component of proteins. These plants attract and trap primarily insects, but occasionally small frogs and rodents in specialised structures.They then digest the `catch', using proteolytic enzymes and absorb the released nutrients. Some plants establish an association with certain bacteria to help produce proteolytic enzymes to digest the insect and absorb the nutrients.

Source: thehindu.com