Photosynthesis and wood structure in Pinus radiata D. Don during dehydration and immediately after rewatering
Photosynthesis and wood structure in Pinus radiata D. Don during dehydration and immediately after rewatering
复制标题
辐射松脱水期间和复水后的光合作用和木材结构
DOI：
10.1111/j.1365-3040.1984.tb01200.x
复制
发表时间：
1984
影响因子：
7.3
通讯作者：
D. Whitehead
中科院分区：
文献类型：
--
作者：
D. Sheriff;D. Whitehead
以辐射松(pinus radiata， D。从无性系亲本砧木扦插而成的树木。这些树有的大约0.4米高，有的大约5米高；它们都是在容器中生长的。在树木浇水充足和缺水后脱水时，测量了大树顶部和底部的茎粗、光合作用速率和针状水势。水分充足植株的水势在小树处最高，在大树顶处最低。当水被截留时，光合作用在大多数情况下不受水势小幅降低的影响，但光合作用速率随着水势进一步降低而下降。在水分充足和部分脱水期间，大树的茎以恒定速率膨胀，而随后的茎收缩和光合作用下降几乎同时发生。在复水后24 h内，水势几乎没有增加，直到2或3 d后才测量到光合作用的显著速率，直到复水后2 d才测量到茎的更新膨胀。水分缺乏减少了新成熟茎管管的管腔直径，但增加了管壁的厚度。在−2.4 MPa左右的水势1个月后，管胞管腔直径和管壁厚度都大大减少，这种减少在复水后不久成熟的管胞中继续存在。
Experiments were carried out onPinus radiata(D. Don) trees grown as cuttings from clonal parent stock. Some of these trees were about 0.4 m high while others were about 5 m high; all were grown in containers. The stem diameters at the tops and at the bottoms of the large trees, rates of photosynthesis, and needle water potentials were measured both when the trees were well watered and as they dehydrated after water was withheld. The water potentials of well‐watered plants was highest in the small trees and lowest at the top of the large trees. When water was withheld, photosynthesis was in most cases unaffected by a small reduction in water potential, but the rate of photosynthesis fell as water potentials declined further. The stems of the large trees expanded at a constant rate when the trees were well watered and for part of the dehydration period, while subsequent stem shrinkage and the fall in photosynthesis both occurred at approximately the same time.Water potentials increased little in the 24 h after rewatering, and significant rates of photosynthesis were not measured until 2 or 3 d later while renewed stem expansion was not measured until 2 d after rewatering.Water deficits reduced the lumen diameter of newly matured stem tracheids, but increased the thickness of their walls. After 1 month of water potentials of about −2.4 MPa, tracheid lumen diameter and wall thickness were both much reduced, and this reduction continued in tracheids maturing shortly after rewatering.