Bio Qs plz help 20點!!!

Why the deficiency of phosphorus in plants will lead to poor growth?


It is because phosphorus is an essential compound to form lipid and then phospholipid bilayer of cell membrane. Therefore, lack of phosphorus result in poor growth of some cellular structure such as cell membrane, mitochondria membrane.

磷是組成脂肪的主要元素，脂肪是組成某些細胞器的重要分子，如細胞膜，線粒體的膜等。




Why lead to poor growth particularly that of root?


Root is responsible for absorption of mineral from soil mainly in active transport. The concentration of mineral (nitrate, magnesum ion) in soil is lower that than cell, so the cell cannot absorb mineral normally by simple diffusion. The absoption of mineral mainly depend on active transport which is a energy needed process due to against concentration gradient.

植物細胞主要以主動運輸吸收泥土中的礦物。



If lack of phosphorous, the mitochondria membrane cannot develop well, so hardly can the plant carry out respiration normally to release energy for active transport. Thus the plant is unable to absorb mineral for growth. As a result, the plant cannot absorb essensial mineral for growth.


Magnesium: make chlorophyllNitrate: make protein.

如果缺磷，腺粒體不能完好發展，呼吸作用主要在粒腺體發生，那呼吸作用也會受到影響。釋放的能量不足，難以進行主動運輸來吸收礦物。



In addition, since the plant cannot absorb mineral well, the low mineral concentration cause high water potential, thus the plant cannot absorb water efficiently by osmosis.

礦物吸收不足，植物細胞維持高水勢，導致水的吸收也受到影響。



Consequently, the plant grow poorly thanks to insufficient water and mineral absorption.