秋茄种源引种深圳湾后幼苗生理生态研究

The physiological-ecology of Kandelia candel seedlings introduced to Shenzhen Bay

将海南琼山、廉江高桥、福建龙海及深圳福田本地的秋茄胚轴 ,培育在深圳福田相同生境中 ,一年以后 ,幼苗的形态生长呈现极显著差异性 ,琼山和福田本地秋茄种源生长最好 ,龙海种源生长最差。生理生态指标值如含水量、叶绿素总量、过氧化氢酶活性、游离脯氨酸含量、电导率等 ,以本地种源最高 ;而植株分枝数、叶片数量及光合速率、蒸腾速率、气孔导度等指标值 ,以琼山种源最高 ,龙海和高桥种源的较低。应用坐标综合评定法 ,初步认为福田本地秋茄是最优种源。

Kandelia candel(D.)is a woody mangrove species growing in intertidal of tropical and subtropical region.It naturally distributed in 5 southeastern provinces (Hainan,Guangdong,Guangxi,Taiwan and Fujian) of China.The distribution,however,has been shrinking due to over exploitation of its habitat.Rehabilitating mangrove vegetation underwent in Shenzhen Bay,a place neighboring Hong Kong in Guangdong Province. K.candel propagated through hypocotyls.Replanting efforts demanded proper provenance.Based upon our experiences,one year old seedlings of K.candel was the best to use.Therefore,to evaluate the performance of various provenance,we conducted a series of experiment in Futian Nature Reserve,Shenzhen Bay,Guangdong Province. Mature hypocotyls of K.candel were randomly collected from 4 sites,Qiongshan (Hainan Province)Longhai (Fujian Provice), Gaoqiao and Futian (Guangdong Province),respectively,in 1997.For uniformity,only intact hypocotyls of similar length and diameter were selected for further experiments.180 hypocotyls from each site were used,totaling 720 hypocotyls.Each hypocotyls was then planted in nutrient bags of 8 cm diameter and 12 cm high.Each bag was filled with soils dug from intertidal of Futian.By randomized blocks design method,these bags were place on triplicate nursery beds at Futian's intertidal zone.Each bed contained 4×60 hypocotyls from each collection site,totaling 240 bags on each bed. In 1998,a series of measurements and analyses were made on the one year old seedlings.The survivorship rate was:Qiongshan>Futian>Gaoqiao>Longhai.The number of leaves was Qiongshan>Futian>Gaoqiao>Longhai.Leaf area was calculated based upon the length and width of 50 randomly selected mature leaves from each provenance.The leaf area was:Futian>Qiongshan>Longhai>Gaoqiao.The results of height and basal diameter measurement showed that the seedlings from Qiongshan had the highest growth rate and followed by those from Futian.The chlorophyll a,b and total chlorophyll content was measured using Spectrophotometric method.Variance analysis of the data indicated that there was significant different of chlorophyll b content but no significant different among chlorophyll a content.The photosynthesis rate,transpiration rate and stomata conductance were measured using Licor-6200 portable photosynthesis device.The photosynthesis rate within the same time frame was Qiongshan>Futian>Gaoqiao and Longhai while the transpiration rate and stomata conductivity of Qiongshan was the highest among the 4 provenance.The total water content of leaves was measure by weighing;the bound water was measured using Abbe refractometer;the free water content was obtained by subtracting the bound water content from the total water content.The ratio of bound water/free water content was Longhai>Futian>Qiongshan and Gaoqiao.This indicated that although Qiongshan provenance had the fast growing rate,it had lower resistant ability ot high salt concentration.On the other hand,Longhai provenance grew slower,but it had higher resistant ability.The catalase activity was measured using Potassium permanganate titration method.The results showed Futian>Gaoqiao>Longshan>Qiongshan.Indicating Futian provenance had the best detoxification abilityl.It was probably because Futian provenance had long grew in and adapted to a highly polluted environment.The free proline contents was measured using Acidic ninhydrin method.The results showed that the free proline content was Longhai>Futian>Qiaonshan>Gaoqiao.Free proline generally accumulated in larger quantity inside plants growing in severe environment condition and reflected the adaptive ability of the plant.Therefore,the results indicated that Gaoqiao provenance,which was from high salt content area,needed only slight accumulation of free proline to grow normally in Futian which had lower salt concentration.On the other hand,those from low salt concentration area of Longhai needed accumulate higher concentration of free proline to grow normally in Futian.The relative electrical conductivity of leaf tissue was Longhai>Ga