Q1: What triggers phototropism in plants?

Plants have specialised cells called ‘photoreceptors’ that detect light intensity and direction. The most important type of photoreceptor involved in phototropism is the Blue Light Receptor (BLR). When BLRs receive blue light radiation, they activate auxin transporters which help move plant hormone auxin from one part of the plant to another.

Q2: How does auxin affect plant growth?

Auxins are hormones that regulate various aspects of plant growth including cell elongation and division. They also play an essential role in promoting gravitropism where roots grow downwards and stems upwards.

Q3: Why do most plants exhibit positive phototrophs instead of negative ones i.e., why do their stems bend towards sunlight rather than away from it?

Scientists believe this response could’ve possibly evolved due to adaptive advantages such as maximising exposure with limited resources especially since sunlight tends to come mainly from only one direction – above us!

Q4: Is there any difference between natural sunrays becoming trigger vis a vis artificial light?

Research has shown that plants respond to artificial light sources in a similar way as they do with sunrays though some factors i.e., wavelengths or insensitivity to certain colour triggers may affect their reaction time and extent of response.

Q5: Is phototropism the only mechanism by which plants grow towards light?

Though it is one aspect, there are other mechanisms involved too! Other methods include heliotropism (the movement of plant organs towards sunlight); solar tracking where leaves & flowers change angle throughout the day maximising sun exposure; shade avoidance whereby increased auxin levels trigger stem growth away from neighbouring vegetation/shade