Translocation in the phloem · 韧皮部中的转运
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| translocation/trænsləʊˈkeɪʃn/ | 运输 | yùn shū |
| source/sɔːs/ | 源 | yuán |
| sink/sɪŋk/ | 库 | kù |
| proton pump/ˈprəʊtɒn pʌmp/ | 质子泵 | zhì zi bèng |
| cotransporter/ˈkɒtrənspɔːtə/ | 共转运体 | gòng zhuǎn yùn tǐ |
| hydrostatic pressure/ˌhaɪdrəˈstætɪk ˈpreʃə/ | 静水压 | jìng shuǐ yā |
| mass flow/mæs fləʊ/ | 集流 | jí liú |
Delivering the sugar
- Translocation 运输 moves sugars (assimilates) through the phloem.
- It carries them from where they are made to where they are needed.
- It is driven by pressure, set up by active loading.
输送糖
- 转运(translocation) 通过 韧皮部 移动糖(同化物)。
- 它把它们从制造的地方运到需要的地方。
- 它由 压力 驱动,这压力由主动装载建立。
Translocation in the phloem transports: · 韧皮部中的转运运输:
Phloem carries dissolved sugars (assimilates), unlike xylem which carries water and minerals. · 韧皮部运输溶解的糖(同化物),不像运输水和矿物质的木质部。
Source 源 and sink 库
- A source is where the assimilate is made or released — e.g. a photosynthesising leaf.
- A sink is where it is used or stored — e.g. a growing root.
- Sucrose and amino acids flow from source to sink.
源和库
- 源(source) 是同化物被 制造或释放 的地方——例如一片进行光合作用的叶。
- 库(sink) 是它被 使用或储存 的地方——例如一条生长的根。
- 蔗糖和氨基酸从源流向库。
In translocation, a "source" is: · 在转运中,一个“源”是:
A source makes/releases the assimilate (e.g. a leaf); a sink uses or stores it (e.g. a growing root). · 源制造/释放同化物(例如一片叶);库使用或储存它(例如一条生长的根)。
Match each term to its meaning. · 把每个术语与它的含义配对。
Sugar is loaded at the source, flows by mass flow, and is unloaded at the sink. · 糖在源处被装载,通过集流流动,在库处被卸载。
Loading at the source
- Companion cells load sucrose into the sieve tube against its gradient — active transport:
- proton pumps 质子泵 pump hydrogen ions out,
- cotransporter 共转运体 proteins then bring sucrose back in with those ions.
- Loading sucrose lowers the water potential in the sieve tube, so water enters by osmosis — raising the hydrostatic pressure 静水压.
在源处装载
- 伴胞把蔗糖 逆着 它的梯度装载进筛管——主动运输:
- 质子泵 把氢离子泵出,
- 协同转运蛋白 然后把蔗糖 连同 那些离子带回来。
- 装载蔗糖 降低筛管中的水势,所以水通过渗透进入——升高 静水压(hydrostatic pressure)。
Sucrose is loaded into the sieve tube at the source by ______ transport (using proton pumps). · 蔗糖在源处通过 ______ 运输(使用质子泵)被装载进筛管。
Companion cells pump H⁺ out, then cotransporters bring sucrose in with the ions — active transport. · 伴胞把 H⁺ 泵出,然后协同转运蛋白把蔗糖连同离子带入——主动运输。
Loading sucrose at the source raises the pressure in the sieve tube because it: · 在源处装载蔗糖升高筛管中的压力,因为它:
More sucrose lowers the water potential; water follows by osmosis, raising hydrostatic pressure. · 更多的蔗糖降低水势;水通过渗透跟随,升高静水压。
Mass flow 集流
- At the sink, sucrose is removed, so water potential rises, water leaves, and pressure falls.
- This makes a pressure difference: high at the source, low at the sink.
- Sap flows from high to low pressure — mass flow.
Translocation by mass flow from source to sink
集流
- 在 库 处,蔗糖被移除,所以水势升高,水离开,压力 下降。
- 这造成一个压力差:在源处 高,在库处 低。
- 汁液从高压流向低压——集流(mass flow)。
从源到库的集流转运
Translocation by mass flow · 通过集流的转运
Step through how sugar moves. Loading at the source pulls water in and raises the pressure, pushing sap to the sink. · 一步步走过糖如何移动。在源处装载把水拉入并升高压力,把汁液推向库。
Put translocation by mass flow in order. · 把通过集流的转运按顺序排列。
Load → water in → high pressure → flow to the sink → unload. · 装载 → 水进入 → 高压 → 流向库 → 卸载。
Phloem can carry sugars both up and down the plant, unlike xylem which only carries water upward. · 韧皮部能把糖沿植物向上和向下运输,不像只把水向上运的木质部。
Sugars flow from any source to any sink — so phloem transport can go up or down; xylem only carries water up. · 糖从任何源流向任何库——所以韧皮部运输能向上或向下;木质部只把水向上运。
You've got it
- translocation = moving assimilates (sucrose, amino acids) in phloem, source → sink
- source = made/released (leaf); sink = used/stored (root)
- loading: active transport (proton pump + cotransport) → lowers water potential → water in → pressure ↑
- mass flow: sap flows from high pressure (source) to low pressure (sink)
你掌握了
- 转运 = 在 韧皮部 中移动同化物(蔗糖、氨基酸),源 → 库
- 源 = 制造/释放(叶);库 = 使用/储存(根)
- 装载:主动运输(质子泵 + 协同转运)→ 降低水势 → 水进入 → 压力 ↑
- 集流:汁液从 高 压(源)流向 低 压(库)