• (1) partitioning of carbohydrates between roots and shoots;
• (2) photosynthetic carbon metabolism;
• (3) formation of reactive O2 species and related photooxidation;
– Aerates
– Standard nutrient level maintained
h
3
2.K+与蛋白质的合成有关。小麦胚芽中分离出的核 糖体，合成蛋白质达到最佳速率时，其所需K+浓 度为130mM。
3 ． K+可能参与tRNA与核糖体结合过程中的几个步 骤。
h
4
Mineral
-P
-K
nutrition of
plants
-N
-S
-Ca
-Fe
h -Mg
5
Plants need elements other than C to grow and develop
N
– now used for vegetable production
K
– roots are cultured in solution, not in soil
S
• More modern growth media
Mg
– Hoagland’s solution → now slightly MODIFIED
h
2
1．钾离子是植物细胞中含量最丰富的阳离子之一。 它的功能：
K+能促进细胞内酶的活性。细胞内有50多种酶或完 全依赖于K+ ，或受K+的激活，如丙酮酸激酶、 谷胱合成酶、6-磷酸果糖激酶等能被K+激活。 作用方式为：同其他一价阳离子都是通过诱导 酶构象的改变，使酶得到活化，从而提高催化 反应的速率。在某些情况下K+能增加酶对底物 的亲和力。K+对膜结合ATP酶也有激活作用。
• Mineral (inorganic) nutrition dependent on C metabolism and vice-versa
– Need for understanding how plants gain nutrition from environment
– People no longer grew their own food! – Need to optimize growth conditions to feed more people – central role of NPK fertilizer to boost yield
different flavors
• Main disadvantage of simple solution culture → as plant grows, it selectively depletes certain minerals
– When one becomes limiting, growth will slow significantly
P
– Murashige and Skoog (M + S)
Fe
• Solutions have high nutrient levels relative to
B
soil
Mn
– Required because the supply is often not
replenished frequently
– Can grow in vermiculite/perlite (inert, non-nutritive) and refertilize daily
• Commercially, it is often cheaper and easier to continuously bathe roots in a nutrient solution (nutrient film technique)
第六章 植物钾营养分子生理
Zichao Mao mzcleemao@
h
1
Why potassium is important
• Potassium (K) play key roles in physiological and biochemical processes, which greatly influence the growth and development of plants. Particular physiological processes affected substantially by inadequate supply of K
h
6
Hydroponic growth facilitated the discovery of essential mineral nutrients
• Further definition of “essential”: Sachs
Ca
(mid-19th century) used hydroponic culture
• (4) regulation of stomatal activity and water regime;
• (5) tolerance against biotic and abiotic stress factors, such as salt stress and drought stress.
• Must integrate carbon with other inorganic minerals taken up by roots from environment
• Together, these elements are the building blocks of complex molecules (proteins, nucleic acids, etc.)
Zn
• Hydroponic culture can be as simple as a
Cu
plant supported in an aerated pot
Mo
– If roots waterloggehd, what happens to yield?
7
Hydroponic culture techniques come in