I am no expert nor do I live in the dessert, but I do have experience with finicky Meyer Lemons. I suggest checking the acidity of your water and your soil. If the ph of your soil is too high, you won't get lemons. There are a variety of methods to lower the ph, none are terrible great, but some may be good enough for you. You might just want to completely re-pot, if the soil is the problem. It also looks like you might have leaf tip burn from salt buildup in your soil. Or it could be from being too dry in the dessert? Or a different type of nutrient deficiency? Do you have a water softener? Do you have hard water, but no softener?

What type of soil is the tree potted in? When was the last time you repotted it? What fertilizer do you use and how often? More information may help us give better advice, but start with test your acidity.