Thích nghi điều kiện tăng trưởng trong vùng đất ngập nước I. Giới thiệu Sự khác biệt lớn nhất giữa đất ngập nước và các nhà máy ở vùng cao là khả năng bắt nguồn từ thực vật đất ngập nước để tồn tại trong đất bão hòa. Ngoài ra, thực vật ngập nước phát triển với ít hoặc không có tiếp xúc với khí quyển, và biểu hiện sự thích nghi với ánh sáng thấp và mức độ carbon dioxide trong cột nước thấp. Nhà máy miễn phí nổi, có thể hấp thụ dinh dưỡng hòa tan trực tiếp từ nước,. | Part II Wetland Plants Adaptations and Reproduction 2001 by CRC Press LLC 4 Adaptations to Growth Conditions in Wetlands I. Introduction The greatest difference between wetland and upland plants is the ability of rooted wetland plants to survive in saturated soil. In addition submerged plants grow with little or no exposure to the atmosphere and exhibit adaptations to low light and low carbon dioxide levels in the water column. Free floating plants able to absorb dissolved nutrients directly from the water thrive without anchoring roots. While many wetland plant adaptations are unique to the wetland habitat some are also found in upland plants such as the enhancement of nutrient uptake through nitrogen fixation or various defenses against herbivores. In this chapter we describe the fate of an upland plant when subjected to anoxic sediments as well as the many adaptations that have evolved in wetland plants as a result of anoxia. We also discuss plant adaptations to high salt and sulfide concentrations in salt marshes and mangrove forests. We give examples of adaptations that allow for improved nutrient uptake or nutrient conservation. We describe adaptations of submerged plants to life underwater the defenses some wetland plants have developed against herbivory and finally wetland plants adaptations to water shortages. A. Aerobic Respiration and Anaerobic Metabolism Every plant cell requires oxygen for aerobic respiration. A green plant produces more oxygen than it needs during daylight hours however the oxygen produced during photosynthesis diffuses away from the plant and very little of it is transported to the root tips. As a consequence the foliage of plants must take in oxygen from the atmosphere and the roots of plants in drained soils must take in oxygen from the soil pore spaces. During aerobic respiration the 6-carbon glucose molecule produced during photosynthesis is broken down to a pair of 3-carbon molecules of pyruvate in glycolysis. When oxygen is .
