Chapter 5 The nutrients translocation in the plant
Chapter 5
The short distance transports of nutrients There are two main steps nutrients translocation in plant after nutrients absorbed by the root. One is the centripetal transport from the rhizoplane through the cortex tissue of the roots towards the xylem vessels of the central cylinder. Another one is the vertical transport from from the root towards the leaves
There are two main steps nutrients translocation in plant after nutrients absorbed by the root. One is the centripetal transport from the rhizoplane through the cortex tissue of the roots towards the xylem vessels of the central cylinder. Another one is the vertical transport from from the root towards the leaves. The short distance transports of nutrients
The short distance transports of nutrients (1)短距离运输( short distance transport)也叫横向运 输( the centripetal transport),或径向运输。指养分由 根的外表皮,穿过皮层进入中柱的过程。 It is the centripetal transport from the rhizoplane through the cortex tissue of the roots towards the xylem vessels of the central cylinder中柱 There are two pathways of ions transportation in the centripetal process.即质外体途径( Apoplastic pathway)和共质体途径( Symplastic pathway)
（1）短距离运输(short distance transport) 也叫横向运 输(the centripetal transport)，或径向运输。指养分由 根的外表皮，穿过皮层进入中柱的过程。 It is the centripetal transport from the rhizoplane through the cortex tissue of the roots towards the xylem vessels of the central cylinder中柱. There are two pathways of ions transportation in the centripetal process. 即质外体途径(Apoplastic pathway)和共质体途径 (Symplastic pathway)。 The short distance transports of nutrients
Rhizodermis Endodermis Xylem Cortex parenchyma Xylem Cell wall Z cytoplasm Cytoplasm Vacuole Symplastic Apoplastic Exodermis Casparian of water and air filled spaces of the cell wall and is in close contact wath h The apoplast(apo, greek- away from the plasma)is the continuous syste the soil medium, the contact often being enhanced by numerous root hairs Water free space(水分自由空间) and Donnan free space(杜南自由空间) Cations interact with the fixed anions in the cell wall(pectin and proteins)and hence their motion is much restricted. The part of the apoplast is also called apparent free space(表观自由空间) as this space appears to be free for diffusion
Symplastic Apoplastic The apoplast (apo, greek= away from the plasma) is the continuous system of water and air filled spaces of the cell wall and is in close contact with the soil medium, the contact often being enhanced by numerous root hairs. Water free space(水分自由空间） and Donnan free space（ 杜南自由空间） Cations interact with the fixed anions in the cell wall (pectin and proteins) and hence their motion is much restricted. The part of the apoplast is also called apparent free space (表观自由空间）as this space appears to be free for diffusion
Apoplast: cell walls spaces between cells (intercellular spaces); filled with air,&water Cell walls Cortex Stele A Early metaxylem Late metaxylem Root hairs Phloem Endodermis Casparian band Exodermis (hypodermis Rhizogen外皮层 被层或表皮
‘Apoplast’: cell walls & spaces between cells (‘intercellular spaces’); filled with ‘air’ & water Cell walls 根被层或表皮层 外皮层