水分与氮素对膜下滴灌棉花叶片叶绿素含量时空分布的影响

通过南疆膜下滴灌棉花不同灌水量和施氮量的田间试验，研究了棉花在不同生育时期及不同叶位叶片叶绿素含量的时空分布。结果表明，在苗期氮肥用量对子叶叶绿素含量的影响显著，随叶位增加，对真叶叶绿素含量的影响越来越小。盛蕾期是棉花叶片叶绿素含量变化最为敏感的时期，并受氮肥施用量的显著影响。在花铃期氮肥用量和叶位均影响棉花叶片叶绿素含量，同时施氮量和滴水量的比值对叶绿素含量的影响也极为明显；在盛铃期，水分与氮肥施用量对棉花叶绿素含量的影响已不显著，但不同叶位之间仍然差异很大。在棉花生长的中后期，滴水量主要影响棉花下部叶片叶绿素含量，而氮素供应量主要影响上部叶片叶绿素含量，中部叶片叶绿素含量同时受水分和氮素的调节。南疆膜下滴灌棉花叶片叶绿素含量，在苗期和盛蕾期以下部叶片最高，花铃期和盛铃期以中部叶片最高，每个叶位叶绿素含量均随着生育时期的推移而逐渐增加。

Chlorophy Space-time Distributing of Cotton Leaves by Water and Nitrogen in Filmed Field by Drip Irrigation

The time-space distribution of chlorophy content in different leaves from various growth loci of cotton in variable development stages were investigated through conducting field trials of different irrigation supply and nitrogen fertilizer dosage under drip irrigation below the films covering cotton.The dosage of nitrogen fertilizer displayed significant effects on chlorophy content in cotyledon leaves of cotton seedlings.However,with the positions of true leaves moving downwards from the tip,nitrogen fertilizer began to exhibit non-significant effects on chlorophy content in cotton leaves.It was in the bud formation stage that chlorophy content of cotton leaves was sensitive to nitrogen element and affected by nitrogen fertilizer markedly.The chlorophy content showed the maximum concentrations in below leaves from cotton plants in the seedling stage and buds' forming stage.But in the flowering stage nitrogen fertilizer dosages and leaves' positions would be as important impact factors to determine chlorophy content in cotton leaves.Meanwhile,the content would be also affected by the ratio of nitrogen dosage to irrigation supply significantly.In the boll development stage chlorophy content of cotton leaves was no longer influenced by water and nitrogen supply.But the contents in cotton leaves from different growth positions still displayed significant difference.In the flowering stage and boll development stage it was in middle leaves to possess the maximum content of chlorophy.In the midst and later development periods of cotton,the water supply from drip irrigation mainly affected chlorophy content of below leaves of cotton plants,and nitrogen dosage affecting chlorophy content of the upper leaves.However chlorophy content of midst leaves was influenced simultaneously and regulated by water and nitrogen supply.Chlorophy contents of cotton leaves from each growth position exhibited an increasing trend with the growth stages under drip irrigation below the film.