The predominant emphasis on harmful effects of environmental stresses on growth of woody plants has obscured some very beneficial effects of such stresses. Slowly increasing stresses may induce physiological adjustment that protects plants from the growth inhibition and/or injury that follow when environmental stresses are abruptly imposed. In addition, short exposures of woody plants to extreme environmental conditions at critical times in their development often improve growth. Furthermore, maintaining harvested seedlings and plant products at very low temperatures extends their longevity. Drought tolerance: Seedlings previously exposed to water stress often undergo less inhibition of growth and other processes following transplanting than do seedlings not previously exposed to such stress. Controlled wetting and drying cycles often promote early budset, dormancy, and drought tolerance. In many species increased drought tolerance following such cycles is associated with osmotic adjustment that ...

Acclimation and adaptive responses of woody plants to environmental stresses

目的 探讨CD25单抗在无血缘关系造血干细胞移植（UHSCT）中对干细胞植入和移植物抗宿主病（GVHD）的作用。方法 27例UHCST中，移植后1、4d给予CD25单抗1mg/kg。结果 27例中，除1例早期死亡外，26例患者造血全部重建。17例发生急性GVHD，其中Ⅱ度以上急性GVHD6例（23％）。复发3例，严重感染3例。26例可评价患者中，19例无病生存（73％）。结论 CD25单抗在UHSCT中对保证干细胞植入和预防GVHD有肯定的作用，白血病复发并不增加。此研究为UHCST和HLA不合的造血干细胞移植提供一个可选择的途径。

Virus diseases that have emerged in the past two decades limit the production of important vegetable crops in tropical, subtropical, and temperate regions worldwide, and many of the causal viruses are transmitted by whiteflies (order Hemiptera, family Aleyrodidae). Most of these whitefly-transmitted viruses are begomoviruses (family Geminiviridae), although whiteflies are also vectors of criniviruses, ipomoviruses, torradoviruses, and some carlaviruses. Factors driving the emergence and establishment of whitefly-transmitted diseases include genetic changes in the virus through mutation and recombination, changes in the vector populations coupled with polyphagy of the main vector, Bemisia tabaci, and long distance traffic of plant material or vector insects due to trade of vegetables and ornamental plants. The role of humans in increasing the emergence of virus diseases is obvious, and the effect that climate change may have in the future is unclear.

Emerging Virus Diseases Transmitted by Whiteflies

ENVIRONMENTAL CONTROL . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Genetics of Sensitivity to Environmental Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control by Day Length . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Control of floral evocation and morphogenesis

The control of floral evocation and morphogenesis

Experiments were conducted with containerized `Tahiti9 lime ( Citrus latifolia Tan.) trees in order to define conditions needed to induce flowering. Cyclical or continuous water stress for 4 to 5 weeks induced flowering. Moderate (−2.25 megapascals, midday) or severe (−3.5 megapascals, midday) water stress as measured by leaf xylem pressure potential, for as little as 2 weeks induced flowering, but the response was more significant in severely stressed trees. Low temperature (18°C day/10°C night) induced a time dependent flowering response much like that of moderate water stress. Significantly negative leaf xylem pressure potentials as compared to controls were found only under water stress treatment, suggesting that a common stress-linked event, separate from low plant water potential is involved in floral induction. Leafless, immature cuttings from mature, field-grown trees were induced to flower by water stress treatment, suggesting that leaves are not essential for a flower inductive response.

/pdf/characterization-of-water-stress-and-low-temperature-effects-p5rb2cn2qs.pdf

Characterization of water stress and low temperature effects on flower induction in citrus.

Apple pollination: A review

Mango flowering involves hormonal regulation of shoot initiation and induction events resulting in reproductive shoot formation. A balance or ratio of endogenously regulated phytohormones, thought to be auxin from leaves and cytokinins from roots, appears to govern the initiation cycle independently from inductive influences. Induction of reproductive or vegetative shoots is thought to be governed by the ratio of a temperature-regulated florigenic promoter and an age regulated vegetative promoter at the time of shoot initiation. Management of off-season flowering in mango trees is being accomplished in the tropics by successfully synchronizing shoot initiation through tip pruning and use of nitrate sprays coupled with management of the stem age to induce flowering such that it can be accomplished during any desired week of the year.

/pdf/reproductive-physiology-of-mango-44os1w8e9r.pdf

Thomas L. Davenport

Papers

Characterization of water stress and low temperature effects on flower induction in citrus.

Apple pollination: A review

Reproductive physiology of mango

Mango (Mangifera indica L.) flowering physiology

Flowering of mango trees in containers as influenced by seasonal temperature and water stress