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所在平台: Udemy |
课程主页: https://www.udemy.com/course/biology-plant-growth-development/
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**课程名称：** 植物生长与发育 **课程概述：** 本课程深入探讨植物生长这一生命活动中最显著的事件之一。我们将研究生长如何表现为大小、面积、长度、高度、体积和细胞数量等参数的不可逆增加，并强调其伴随的原生质物质的增加。课程重点在于植物的生长区域——分生组织，特别是根尖和芽尖分生组织，它们在植物轴的伸长生长中起着关键作用。 我们将分析植物生长可分为潜伏期、对数期和衰老期三个主要阶段，以及细胞分裂后可能发生的算术或几何生长模式。课程还将阐述细胞失去分裂能力后如何发生分化，以及分化如何导致与细胞功能相匹配的结构的形成。我们将探讨细胞、组织和器官分化的普遍原则，以及植物在分化后可能发生的去分化和再分化现象。由于植物分化是开放性的，其发育也具有灵活性，发育被定义为生长和分化的总和。我们将研究植物在其发育过程中表现出的可塑性。 此外，课程还将重点关注影响植物生长与发育的内在和外在因素。内在因素包括植物生长调节剂（PGR），如生长素、赤节素、细胞分裂素、脱落酸和乙烯。我们将研究这些PGR的合成部位、它们如何调控不同的分化和发育事件，以及它们所表现出的多元生理效应，包括协同或拮抗作用。外在因素则包括光照、温度、营养、氧气、重力等。 课程还将深入研究光周期对某些植物开花的影响，区分短日照植物、长日照植物和日中性植物。最后，我们将探讨某些植物需要低温处理才能促进后期开花的现象，即春化作用。
DescriptionGrowth is one of the most conspicuous events in any living organism. It is an irreversible increase expressed in parameters such as size, area, length, height, volume, cell number etc. It conspicuously involves increased protoplasmic material. In plants, meristems are the sites of growth. Root and shoot apical meristems sometimes alongwith intercalary meristem, contribute to the elongation growth of plant axes. Growth is indeterminate in higher plants. Following cell division in root and shoot apical meristem cells, the growth could be arithmetic or geometrical.Growth may not be and generally is not sustained at a high rate throughout the life of cell/tissue/organ/organism. One can define three principle phases of growth - the lag, the log and the senescent phase. When a cell loses the capacity to divide, it leads to differentiation. Differentiation results in development of structures that is commensurate with the function the cells finally has to perform. General principles for differentiation for cell, tissues and organs are similar. A differentiated cell may dedifferentiate and then redifferentiate. Since differentiation in plants is open, thedevelopment could also be flexible, i.e., the development is the sum of growth and differentiation. Plant exhibit plasticity in development.Plant growth and development are under the control of both intrinsic and extrinsic factors. Intercellular intrinsic factors are the chemical substances, called plant growth regulators (PGR). There are diverse groups of PGRs in plants, principally belonging to five groups: auxins, gibberellins, cytokinins, abscisic acid and ethylene. These PGRs are synthesised in various parts of the plant; they control differentdifferentiation and developmental events. Any PGR has diverse physiological effects on plants. Diverse PGRs also manifest similar effects. PGRs may act synergistically or antagonistically. Plant growth and development is also affected by light, temperature, nutrition, oxygen status, gravity and such external factors.Flowering in some plants is induced only when exposed to certain duration of photoperiod. Depending on the nature of photoperiod requirements, the plants are called short day plants, long day plants and day-neutral plants. Certain plants also need to be exposed to low temperature so as to hasten flowering later in life. This treatement is known as vernalisation.
