膜下滴灌条件下氮肥运筹对棉花叶片^(14)C同化物运转及激素含量的影响

Effect of nitrogen management on translocation of ^(14)C assimilate and endogenous hormone contents in cotton with drip irrigation under film mulch

以新疆早熟高产棉花品种为材料,研究了膜下滴灌条件下氮素运筹对新疆早熟高产棉花叶片14C同化物运转分配及内源激素含量的影响。结果表明:在高产棉花施氮量270 kg·hm-2的条件下,与棉花3个生育期等氮量施肥处理相比,前重处理(开花前施80%的氮)提高了叶片中吲哚乙酸(IAA)、玉米素及其核苷(Z+ZR)的含量,增加生育后期脱落酸(ABA)、异戊烯基腺嘌呤及其核苷(iP+iPA)含量,促进了同化物向棉铃运输,从而获得较高的籽棉产量;后重处理(开花前施50%的氮)虽增加了叶片ABA含量,提高同化物向棉铃分配的比例,显著增加铃重,但降低了叶片中IAA、Z+ZR含量,造成叶片过快衰老,进而导致籽棉产量显著降低。因此,膜下滴灌条件下,在重视氮肥基施的基础上,适度加大生育中后期追施比例,通过调节棉花叶片ABA含量,促进光合产物优先向棉铃运输,增加铃重,有利于充分挖掘膜下滴灌技术节水增效潜力。

In this paper,the effect of nitrogen application management on translocation and partitioning of 14C assimilates and endogenous hormone levels of cotton leaf under mulched drip irrigation was studied using a cotton variety with early maturing and high yield.The total nitrogen amount applied is 270 kg · hm-2.Three application methods are conducted,one is applying 80% of N before the flowering stage,second method is applying equivalent nitrogen during the three main N applying stages,and the last one is applying 50% of N before the flowering stage.The results showed that compared with the treatment of equivalent nitrogen application rate of 3 growth stages,the high nitrogen application rate in the early stage the content of indole acetic acid （IAA）,zeatin and its nucleoside （Z ＋ ZR） of cotton leaf,and the contents of abscisic acid （ABA）,isopenteny ladenime and its nucleoside （iP ＋ iPA） are all inproved during the late growth period of cotton,the 14C assimilates translocation to cotton boll,is promoted and increased the yield of seed cotton.Although for the high nitrogen application rate in the late stage the ABA content in leaves,the proportion of 14C assimilates partitioning to the boll,and boll weight were increased significantly,but the contents of IAA,Z ＋ ZR of cotton leaf,resulted in rapid leaf aging were decreased and the yield of seed cotton decreased significantly.These results suggested that certain proportion of nitrogen fertilizer should be applied as basal fertilizer with mulched drip irrigation,and the proportion of additional nitrogen at late stage,should be appropriately increased which can affect the contents of ABA in leaves and accelerate the transportation of photosynthetic product to leaves,and increase boll weight.These measures for nitrogen management will fully exploit the water-saving potential of mulched drip Irrigation.