Altitudinal variation of resin ducts in Pinus taiwanensis Hayata (Pinaceae) needles
The variation of resin ducts in needles of Pinus taiwanensis along an altitude gradient (700 m- 3,100 m) in central Taiwan is revealed for the first time in this study, including position type, number, size, arrangement pattern and anatomical structural variation. Three types of resin ducts-medial, external and septal-were found according to their relative positions in the mesophyll. All needles sampled showed combinations of these three resin duct types. Mostly, 3-7 resin ducts were found in the mesophyll per needle, and the number of resin ducts was significantly greater at mid altitudes than at high and low altitudes. Septal ducts decreased in number with an increase in altitude; however, needles from mid altitudes had more external ducts. Eight patterns (basic and patterns I-VII) of resin ducts in the mesophyll of needles were delineated to present the arrangement variations. In addition to the primary ducts found in the mesophyll, we found the rare bundle sheath ducts in some needles, and their frequencies decreased obviously with an increase in altitude. The consistent combination feature of medial, external, and septal ducts in needles of P. taiwanensis from Taiwan could be easily distinguished from those with medial ducts from mainland China. However, this difference has unrecognized before, and it should be considered in future taxonomic work.
Can climate and soil conditions change the morpho-anatomy among individuals from different localities ? A case study in Aldama grandiflora ( Asteraceae )
Vegetative aerial organs are considerably more exposed to environmental conditions and can reflect the specific adaptations of plants to their local environment. Aldama grandiflora species are known to be widely distributed in Brazil; therefore, individuals from different populations of this species are thought to be exposed to different abiotic and biotic conditions. Several anatomical studies conducted on Brazilian Aldama species have mainly focused on the qualitative anatomical characters or traits of these species, but not on their quantitative traits. In this study, we evaluated whether climate and soil conditions can change the morphometry among individuals of A. grandiflora collected from six sites in the Goiás State, Brazil, by assessing their anatomical characters. Further, soil sampling was performed, and climate data were collected from all the six sites. The analysis indicated few statistical differences among the populations evaluated, showing that A. grandiflora presented consistent leaf and stem anatomical characteristics. The small morpho-anatomical differences found among individuals of the different populations evaluated, reflected the soil conditions in which these populations were grown. Therefore, environmental factors have a significant influence on the morpho-anatomy of Aldama grandiflora.
The effect of constitutive resistance in lodgepole pine ( Pinus contorta ) and Scots pine ( P. sylvestris ) on oviposition by three pine feeding herbivores
The acceptance of different provenances or seed origins of lodgepole pine Pinus contorta and Scots pine P. sylvestris as suitable oviposition sites was found to vary as a function of both tree age and insect species. Experiments on seedling lodgepole pine revealed that the pine sawfly, Neodiprion sertifer Geoffroy (Hymenoptera: Diprionidae), and the larch bud moth, Zeiraphera diniana Guennee (Lepidoptera: Tortricidae), preferred more southerly provenances of lodgepole pine. The pine beauty moth, Panolis flammea Denis & Schiffermuller (Lepidoptera: Noctuidae), however, preferred more northerly provenances. On mature lodgepole pine however, P. flammea exhibited a host change, preferring the more southerly provenances. Neodiprion sertifer showed a similar preference on both seedling and mature provenances. The results of this study suggest that some provenances of lodgepole pine become more resistant to attack by P. flammea as they mature, while others become more susceptible. This may be related to the feeding, strategies of the two insects: P. flammea larvae feed on current year foliage while N. sertifer feeds only on previous year foliage. It is possible that the mechanism for chemical defence of new shoots changes as the trees mature, and to a varying degree in different provenances, while defence of the previous years foliage remains unchanged. Results also indicate that odour alone as opposed to odour plus visual stimulation may invoke different ovipositional behaviour in N. sertifer .