Eccentric Growth but No Compression Wood in a Horizontal Stem of Cycas Micronesica (cycadales)
نویسندگان
چکیده
A single 1.41-m-long trunk of Cycas micronesica K.D. Hill was found growing horizontally in natural habitat on the island of Guam. Transverse sections of the trunk showed enhancement of secondary vascular tissues on the lower side by the production of more arcs of accessory vascular cambia and more parenchyma as compared to the upper side. Xylem tracheids were similar in upper and lower sides. There was no evidence of compression wood tracheids as seen in conifers.
منابع مشابه
Diversity in Cycas (Cycadales: Cycadaceae) Species Offered as Larval Food Influences Fecundity of Chilades pandava (Lepidoptera: Lycaenidae) Adults
Chilades pandava (Lepidoptera: Lycaenidae) larval food quality was studied to determine its influence on adult life history traits. A wild population from Cycas nongnoochiae (Cycadales: Cycadaceae) endemic habitat behaved similarly to the population collected from a garden setting. Cycas micronesica, Cycas revoluta, and Cycas seemannii leaves were used as high-quality food, whereas C nongnoochi...
متن کاملIncreased threat of island endemic tree’s extirpation via invasion-induced decline of intrinsic resistance to recurring tropical cyclones
Cycas micronesica populations in Guam have been threatened by the invasion of the armored scale Aulacaspis yasumatsui. I integrate four factors that illuminate an acute need for intervention to reduce an unprecedented threat caused by the invasion. First, mechanical failure of healthy C. micronesica trees during catastrophic winds is rare because of the cycad tree's unique pachycaulis stem desi...
متن کاملCone thermogenesis and its limits in the tropical Cycas micronesica (Cycadaceae): association with cone growth, dehiscence, and post-dehiscence phases.
UNLABELLED PREMISE OF THE STUDY Thermogenesis is a prominent pollination-related feature of cycad cones and is generally assumed to play a role in pollination. Although typically studied just before, during, and immediately after the cones' pollination phase, thermogenesis may be present in other cone developmental phases. • METHODS We assayed thermogenesis in Cycas micronesica, Guam's end...
متن کاملThree invasive insects alter Cycas micronesica leaf chemistry and predict changes in biogeochemical cycling
Leaf litter chemical traits were measured for Cycas micronesica plants in Guam following leaf herbivory by the scale Aulacaspis yasumatsui, the butterfly Chilades pandava caterpillar, or the leaf miner Erechthias sp. to determine the influence of the non-native pests on litter quality. Scale herbivory increased litter phenols above those of undamaged leaves but did not influence lignin or cellu...
متن کاملDoes cycad aulacaspis scale (Aulacaspis yasumatsui, Hemiptera: Diaspididae) play a direct role in causing soil phytotoxicity?
Cycad aulacaspis scale (CAS, Aulacaspis yasumatsui, Hemiptera: Diaspididae) was accidentally introduced to Guam in 2003, and has caused acute mortality of the dominant, endemic forest tree Cycas micronesica. A phytotoxic legacy in the soils beneath cycad trees killed by CAS over a period of about three years has been demonstrated. The origin of the toxicity may be large quantities of CAS-encrus...
متن کامل