Teeri J A
Barnes Laboratory, The University of Chicago, 5630 S. Ingleside Avenue, 60637, Chicago, IL, USA.
Oecologia. 1984 Sep;64(1):68-73. doi: 10.1007/BF00377545.
Plants of Dudleya blochmanae were studied over a growing season (December-June) in their native habitat on the central California coast. During the season soil water potential fluctuatdd widely, becoming unmeasurably negative (<-5.0 MPa) by early May. In contrast, leaf water potential did not fluctuate greatly with the most negative value of-0.56 MPa occurring in June. The leaves exhibited nocturnal accumulation of titratable acidity at all sampling periods, with the greatest magnitudes of accumulation occurring late in the growing season. The fruits also exhibited nocturnal accumulation of titratable acidity. The biomass δC values of all organs were most negative in December and least negative in June. The findings confirmed earlier suggestions that there may be biologically important differences in carbon isotope content among the various organs of a single plant of D. blochmanae. The water potential of thephotosynthetic organs was highly correlated (r=0.84) with the biomas δC value. A greenhouse study demonstrated that the fruits exhibit an, apical dominance with regard to maintenance of plant water potential during drought.
在加利福尼亚州中部海岸的原生栖息地，对布洛赫曼氏仙女杯（Dudleya blochmanae）的植株进行了一个生长季（12月至6月）的研究。在这个季节里，土壤水势波动很大，到5月初时变得极低，无法测量（<-5.0 MPa）。相比之下，叶片水势波动不大，6月出现的最负值为-0.56 MPa。在所有采样期，叶片都表现出夜间可滴定酸度的积累，积累量最大的时候出现在生长季后期。果实也表现出夜间可滴定酸度的积累。所有器官的生物量δC值在12月最负，6月最不负。这些发现证实了早期的推测，即对于布洛赫曼氏仙女杯的单株植物而言，其不同器官的碳同位素含量可能存在生物学上的重要差异。光合器官的水势与生物量δC值高度相关（r=0.84）。一项温室研究表明，在干旱期间，果实在维持植物水势方面表现出顶端优势。
